ETH Price: $2,024.47 (+1.09%)

Transaction Decoder

Block:
23493803 at Oct-03-2025 12:54:59 AM +UTC
Transaction Fee:
0.00003525951553718 ETH $0.07
Gas Used:
53,636 Gas / 0.657385255 Gwei

Emitted Events:

437 TokenProxy.0x8c5be1e5ebec7d5bd14f71427d1e84f3dd0314c0f7b2291e5b200ac8c7c3b925( 0x8c5be1e5ebec7d5bd14f71427d1e84f3dd0314c0f7b2291e5b200ac8c7c3b925, 0x000000000000000000000000ff4da1a59b1130f736c4b76b070e7039a22fda8e, 0x000000000000000000000000bbbfd134e9b44bfb5123898ba36b01de7ab93d98, 0000000000000000000000000000000000000000000000008987647e9c1f0000 )

Account State Difference:

  Address   Before After State Difference Code
0xAcE8E719...65c2119F1
(BuilderNet)
94.755361611785067992 Eth94.755388429785067992 Eth0.000026818
0xfF4DA1a5...9A22fDA8e
0.000408670265489424 Eth
Nonce: 1
0.000373410749952244 Eth
Nonce: 2
0.00003525951553718

Execution Trace

TokenProxy.095ea7b3( )
  • USDon.approve( spender=0xBBbfD134E9b44BfB5123898BA36b01dE7ab93d98, amount=9910000000000000000 ) => ( True )
    File 1 of 2: TokenProxy
    /**SPDX-License-Identifier: BUSL-1.1
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      ██▀ ▄██▀▀╙╙▀▀██▄ └██µ           ,,       ,,      ,     ,,,            ,,,
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    ██  ██ ╒█▀'   ╙█▌ ╙█▌ ██     ▐██      ███  █████,  ██  ██▌    └██▌  ██▌     └██▌
    ██ ▐█▌ ██      ╟█  █▌ ╟█     ██▌      ▐██  ██ └███ ██  ██▌     ╟██ j██       ╟██
    ╟█  ██ ╙██    ▄█▀ ▐█▌ ██     ╙██      ██▌  ██   ╙████  ██▌    ▄██▀  ██▌     ,██▀
     ██ "██, ╙▀▀███████████⌐      ╙████████▀   ██     ╙██  ███████▀▀     ╙███████▀`
      ██▄ ╙▀██▄▄▄▄▄,,,                ¬─                                    '─¬
       ╙▀██▄ '╙╙╙▀▀▀▀▀▀▀▀
          ╙▀▀██████R⌐
     */
    pragma solidity 0.8.16;
    import "contracts/external/openzeppelin/contracts/proxy/TransparentUpgradeableProxy.sol";
    contract TokenProxy is TransparentUpgradeableProxy {
      constructor(
        address _logic,
        address _admin,
        bytes memory _data
      ) TransparentUpgradeableProxy(_logic, _admin, _data) {}
    }
    // SPDX-License-Identifier: MIT
    // OpenZeppelin Contracts v4.4.1 (proxy/transparent/TransparentUpgradeableProxy.sol)
    pragma solidity ^0.8.0;
    import "contracts/external/openzeppelin/contracts/proxy/ERC1967Proxy.sol";
    /**
     * @dev This contract implements a proxy that is upgradeable by an admin.
     *
     * To avoid https://medium.com/nomic-labs-blog/malicious-backdoors-in-ethereum-proxies-62629adf3357[proxy selector
     * clashing], which can potentially be used in an attack, this contract uses the
     * https://blog.openzeppelin.com/the-transparent-proxy-pattern/[transparent proxy pattern]. This pattern implies two
     * things that go hand in hand:
     *
     * 1. If any account other than the admin calls the proxy, the call will be forwarded to the implementation, even if
     * that call matches one of the admin functions exposed by the proxy itself.
     * 2. If the admin calls the proxy, it can access the admin functions, but its calls will never be forwarded to the
     * implementation. If the admin tries to call a function on the implementation it will fail with an error that says
     * "admin cannot fallback to proxy target".
     *
     * These properties mean that the admin account can only be used for admin actions like upgrading the proxy or changing
     * the admin, so it's best if it's a dedicated account that is not used for anything else. This will avoid headaches due
     * to sudden errors when trying to call a function from the proxy implementation.
     *
     * Our recommendation is for the dedicated account to be an instance of the {ProxyAdmin} contract. If set up this way,
     * you should think of the `ProxyAdmin` instance as the real administrative interface of your proxy.
     */
    contract TransparentUpgradeableProxy is ERC1967Proxy {
      /**
       * @dev Initializes an upgradeable proxy managed by `_admin`, backed by the implementation at `_logic`, and
       * optionally initialized with `_data` as explained in {ERC1967Proxy-constructor}.
       */
      constructor(
        address _logic,
        address admin_,
        bytes memory _data
      ) payable ERC1967Proxy(_logic, _data) {
        assert(
          _ADMIN_SLOT == bytes32(uint256(keccak256("eip1967.proxy.admin")) - 1)
        );
        _changeAdmin(admin_);
      }
      /**
       * @dev Modifier used internally that will delegate the call to the implementation unless the sender is the admin.
       */
      modifier ifAdmin() {
        if (msg.sender == _getAdmin()) {
          _;
        } else {
          _fallback();
        }
      }
      /**
       * @dev Returns the current admin.
       *
       * NOTE: Only the admin can call this function. See {ProxyAdmin-getProxyAdmin}.
       *
       * TIP: To get this value clients can read directly from the storage slot shown below (specified by EIP1967) using the
       * https://eth.wiki/json-rpc/API#eth_getstorageat[`eth_getStorageAt`] RPC call.
       * `0xb53127684a568b3173ae13b9f8a6016e243e63b6e8ee1178d6a717850b5d6103`
       */
      function admin() external ifAdmin returns (address admin_) {
        admin_ = _getAdmin();
      }
      /**
       * @dev Returns the current implementation.
       *
       * NOTE: Only the admin can call this function. See {ProxyAdmin-getProxyImplementation}.
       *
       * TIP: To get this value clients can read directly from the storage slot shown below (specified by EIP1967) using the
       * https://eth.wiki/json-rpc/API#eth_getstorageat[`eth_getStorageAt`] RPC call.
       * `0x360894a13ba1a3210667c828492db98dca3e2076cc3735a920a3ca505d382bbc`
       */
      function implementation() external ifAdmin returns (address implementation_) {
        implementation_ = _implementation();
      }
      /**
       * @dev Changes the admin of the proxy.
       *
       * Emits an {AdminChanged} event.
       *
       * NOTE: Only the admin can call this function. See {ProxyAdmin-changeProxyAdmin}.
       */
      function changeAdmin(address newAdmin) external virtual ifAdmin {
        _changeAdmin(newAdmin);
      }
      /**
       * @dev Upgrade the implementation of the proxy.
       *
       * NOTE: Only the admin can call this function. See {ProxyAdmin-upgrade}.
       */
      function upgradeTo(address newImplementation) external ifAdmin {
        _upgradeToAndCall(newImplementation, bytes(""), false);
      }
      /**
       * @dev Upgrade the implementation of the proxy, and then call a function from the new implementation as specified
       * by `data`, which should be an encoded function call. This is useful to initialize new storage variables in the
       * proxied contract.
       *
       * NOTE: Only the admin can call this function. See {ProxyAdmin-upgradeAndCall}.
       */
      function upgradeToAndCall(address newImplementation, bytes calldata data)
        external
        payable
        ifAdmin
      {
        _upgradeToAndCall(newImplementation, data, true);
      }
      /**
       * @dev Returns the current admin.
       */
      function _admin() internal view virtual returns (address) {
        return _getAdmin();
      }
      /**
       * @dev Makes sure the admin cannot access the fallback function. See {Proxy-_beforeFallback}.
       */
      function _beforeFallback() internal virtual override {
        require(
          msg.sender != _getAdmin(),
          "TransparentUpgradeableProxy: admin cannot fallback to proxy target"
        );
        super._beforeFallback();
      }
    }
    // SPDX-License-Identifier: MIT
    // OpenZeppelin Contracts v4.4.1 (proxy/ERC1967/ERC1967Proxy.sol)
    pragma solidity ^0.8.0;
    import "contracts/external/openzeppelin/contracts/proxy/Proxy.sol";
    import "contracts/external/openzeppelin/contracts/proxy/ERC1967Upgrade.sol";
    /**
     * @dev This contract implements an upgradeable proxy. It is upgradeable because calls are delegated to an
     * implementation address that can be changed. This address is stored in storage in the location specified by
     * https://eips.ethereum.org/EIPS/eip-1967[EIP1967], so that it doesn't conflict with the storage layout of the
     * implementation behind the proxy.
     */
    contract ERC1967Proxy is Proxy, ERC1967Upgrade {
      /**
       * @dev Initializes the upgradeable proxy with an initial implementation specified by `_logic`.
       *
       * If `_data` is nonempty, it's used as data in a delegate call to `_logic`. This will typically be an encoded
       * function call, and allows initializating the storage of the proxy like a Solidity constructor.
       */
      constructor(address _logic, bytes memory _data) payable {
        assert(
          _IMPLEMENTATION_SLOT ==
            bytes32(uint256(keccak256("eip1967.proxy.implementation")) - 1)
        );
        _upgradeToAndCall(_logic, _data, false);
      }
      /**
       * @dev Returns the current implementation address.
       */
      function _implementation()
        internal
        view
        virtual
        override
        returns (address impl)
      {
        return ERC1967Upgrade._getImplementation();
      }
    }
    // SPDX-License-Identifier: MIT
    // OpenZeppelin Contracts (last updated v4.5.0) (proxy/Proxy.sol)
    pragma solidity ^0.8.0;
    /**
     * @dev This abstract contract provides a fallback function that delegates all calls to another contract using the EVM
     * instruction `delegatecall`. We refer to the second contract as the _implementation_ behind the proxy, and it has to
     * be specified by overriding the virtual {_implementation} function.
     *
     * Additionally, delegation to the implementation can be triggered manually through the {_fallback} function, or to a
     * different contract through the {_delegate} function.
     *
     * The success and return data of the delegated call will be returned back to the caller of the proxy.
     */
    abstract contract Proxy {
      /**
       * @dev Delegates the current call to `implementation`.
       *
       * This function does not return to its internal call site, it will return directly to the external caller.
       */
      function _delegate(address implementation) internal virtual {
        assembly {
          // Copy msg.data. We take full control of memory in this inline assembly
          // block because it will not return to Solidity code. We overwrite the
          // Solidity scratch pad at memory position 0.
          calldatacopy(0, 0, calldatasize())
          // Call the implementation.
          // out and outsize are 0 because we don't know the size yet.
          let result := delegatecall(gas(), implementation, 0, calldatasize(), 0, 0)
          // Copy the returned data.
          returndatacopy(0, 0, returndatasize())
          switch result
            // delegatecall returns 0 on error.
            case 0 {
              revert(0, returndatasize())
            }
            default {
              return(0, returndatasize())
            }
        }
      }
      /**
       * @dev This is a virtual function that should be overriden so it returns the address to which the fallback function
       * and {_fallback} should delegate.
       */
      function _implementation() internal view virtual returns (address);
      /**
       * @dev Delegates the current call to the address returned by `_implementation()`.
       *
       * This function does not return to its internall call site, it will return directly to the external caller.
       */
      function _fallback() internal virtual {
        _beforeFallback();
        _delegate(_implementation());
      }
      /**
       * @dev Fallback function that delegates calls to the address returned by `_implementation()`. Will run if no other
       * function in the contract matches the call data.
       */
      fallback() external payable {
        _fallback();
      }
      /**
       * @dev Fallback function that delegates calls to the address returned by `_implementation()`. Will run if call data
       * is empty.
       */
      receive() external payable {
        _fallback();
      }
      /**
       * @dev Hook that is called before falling back to the implementation. Can happen as part of a manual `_fallback`
       * call, or as part of the Solidity `fallback` or `receive` functions.
       *
       * If overriden should call `super._beforeFallback()`.
       */
      function _beforeFallback() internal virtual {}
    }
    // SPDX-License-Identifier: MIT
    // OpenZeppelin Contracts (last updated v4.5.0) (proxy/ERC1967/ERC1967Upgrade.sol)
    pragma solidity ^0.8.2;
    import "contracts/external/openzeppelin/contracts/proxy/IBeacon.sol";
    import "contracts/external/openzeppelin/contracts/proxy/draft-IERC1822.sol";
    import "contracts/external/openzeppelin/contracts/utils/Address.sol";
    import "contracts/external/openzeppelin/contracts/utils/StorageSlot.sol";
    /**
     * @dev This abstract contract provides getters and event emitting update functions for
     * https://eips.ethereum.org/EIPS/eip-1967[EIP1967] slots.
     *
     * _Available since v4.1._
     *
     * @custom:oz-upgrades-unsafe-allow delegatecall
     */
    abstract contract ERC1967Upgrade {
      // This is the keccak-256 hash of "eip1967.proxy.rollback" subtracted by 1
      bytes32 private constant _ROLLBACK_SLOT =
        0x4910fdfa16fed3260ed0e7147f7cc6da11a60208b5b9406d12a635614ffd9143;
      /**
       * @dev Storage slot with the address of the current implementation.
       * This is the keccak-256 hash of "eip1967.proxy.implementation" subtracted by 1, and is
       * validated in the constructor.
       */
      bytes32 internal constant _IMPLEMENTATION_SLOT =
        0x360894a13ba1a3210667c828492db98dca3e2076cc3735a920a3ca505d382bbc;
      /**
       * @dev Emitted when the implementation is upgraded.
       */
      event Upgraded(address indexed implementation);
      /**
       * @dev Returns the current implementation address.
       */
      function _getImplementation() internal view returns (address) {
        return StorageSlot.getAddressSlot(_IMPLEMENTATION_SLOT).value;
      }
      /**
       * @dev Stores a new address in the EIP1967 implementation slot.
       */
      function _setImplementation(address newImplementation) private {
        require(
          Address.isContract(newImplementation),
          "ERC1967: new implementation is not a contract"
        );
        StorageSlot.getAddressSlot(_IMPLEMENTATION_SLOT).value = newImplementation;
      }
      /**
       * @dev Perform implementation upgrade
       *
       * Emits an {Upgraded} event.
       */
      function _upgradeTo(address newImplementation) internal {
        _setImplementation(newImplementation);
        emit Upgraded(newImplementation);
      }
      /**
       * @dev Perform implementation upgrade with additional setup call.
       *
       * Emits an {Upgraded} event.
       */
      function _upgradeToAndCall(
        address newImplementation,
        bytes memory data,
        bool forceCall
      ) internal {
        _upgradeTo(newImplementation);
        if (data.length > 0 || forceCall) {
          Address.functionDelegateCall(newImplementation, data);
        }
      }
      /**
       * @dev Perform implementation upgrade with security checks for UUPS proxies, and additional setup call.
       *
       * Emits an {Upgraded} event.
       */
      function _upgradeToAndCallUUPS(
        address newImplementation,
        bytes memory data,
        bool forceCall
      ) internal {
        // Upgrades from old implementations will perform a rollback test. This test requires the new
        // implementation to upgrade back to the old, non-ERC1822 compliant, implementation. Removing
        // this special case will break upgrade paths from old UUPS implementation to new ones.
        if (StorageSlot.getBooleanSlot(_ROLLBACK_SLOT).value) {
          _setImplementation(newImplementation);
        } else {
          try IERC1822Proxiable(newImplementation).proxiableUUID() returns (
            bytes32 slot
          ) {
            require(
              slot == _IMPLEMENTATION_SLOT,
              "ERC1967Upgrade: unsupported proxiableUUID"
            );
          } catch {
            revert("ERC1967Upgrade: new implementation is not UUPS");
          }
          _upgradeToAndCall(newImplementation, data, forceCall);
        }
      }
      /**
       * @dev Storage slot with the admin of the contract.
       * This is the keccak-256 hash of "eip1967.proxy.admin" subtracted by 1, and is
       * validated in the constructor.
       */
      bytes32 internal constant _ADMIN_SLOT =
        0xb53127684a568b3173ae13b9f8a6016e243e63b6e8ee1178d6a717850b5d6103;
      /**
       * @dev Emitted when the admin account has changed.
       */
      event AdminChanged(address previousAdmin, address newAdmin);
      /**
       * @dev Returns the current admin.
       */
      function _getAdmin() internal view returns (address) {
        return StorageSlot.getAddressSlot(_ADMIN_SLOT).value;
      }
      /**
       * @dev Stores a new address in the EIP1967 admin slot.
       */
      function _setAdmin(address newAdmin) private {
        require(newAdmin != address(0), "ERC1967: new admin is the zero address");
        StorageSlot.getAddressSlot(_ADMIN_SLOT).value = newAdmin;
      }
      /**
       * @dev Changes the admin of the proxy.
       *
       * Emits an {AdminChanged} event.
       */
      function _changeAdmin(address newAdmin) internal {
        emit AdminChanged(_getAdmin(), newAdmin);
        _setAdmin(newAdmin);
      }
      /**
       * @dev The storage slot of the UpgradeableBeacon contract which defines the implementation for this proxy.
       * This is bytes32(uint256(keccak256('eip1967.proxy.beacon')) - 1)) and is validated in the constructor.
       */
      bytes32 internal constant _BEACON_SLOT =
        0xa3f0ad74e5423aebfd80d3ef4346578335a9a72aeaee59ff6cb3582b35133d50;
      /**
       * @dev Emitted when the beacon is upgraded.
       */
      event BeaconUpgraded(address indexed beacon);
      /**
       * @dev Returns the current beacon.
       */
      function _getBeacon() internal view returns (address) {
        return StorageSlot.getAddressSlot(_BEACON_SLOT).value;
      }
      /**
       * @dev Stores a new beacon in the EIP1967 beacon slot.
       */
      function _setBeacon(address newBeacon) private {
        require(
          Address.isContract(newBeacon),
          "ERC1967: new beacon is not a contract"
        );
        require(
          Address.isContract(IBeacon(newBeacon).implementation()),
          "ERC1967: beacon implementation is not a contract"
        );
        StorageSlot.getAddressSlot(_BEACON_SLOT).value = newBeacon;
      }
      /**
       * @dev Perform beacon upgrade with additional setup call. Note: This upgrades the address of the beacon, it does
       * not upgrade the implementation contained in the beacon (see {UpgradeableBeacon-_setImplementation} for that).
       *
       * Emits a {BeaconUpgraded} event.
       */
      function _upgradeBeaconToAndCall(
        address newBeacon,
        bytes memory data,
        bool forceCall
      ) internal {
        _setBeacon(newBeacon);
        emit BeaconUpgraded(newBeacon);
        if (data.length > 0 || forceCall) {
          Address.functionDelegateCall(IBeacon(newBeacon).implementation(), data);
        }
      }
    }
    // SPDX-License-Identifier: MIT
    // OpenZeppelin Contracts v4.4.1 (proxy/beacon/IBeacon.sol)
    pragma solidity ^0.8.0;
    /**
     * @dev This is the interface that {BeaconProxy} expects of its beacon.
     */
    interface IBeacon {
      /**
       * @dev Must return an address that can be used as a delegate call target.
       *
       * {BeaconProxy} will check that this address is a contract.
       */
      function implementation() external view returns (address);
    }
    // SPDX-License-Identifier: MIT
    // OpenZeppelin Contracts (last updated v4.5.0) (interfaces/draft-IERC1822.sol)
    pragma solidity ^0.8.0;
    /**
     * @dev ERC1822: Universal Upgradeable Proxy Standard (UUPS) documents a method for upgradeability through a simplified
     * proxy whose upgrades are fully controlled by the current implementation.
     */
    interface IERC1822Proxiable {
      /**
       * @dev Returns the storage slot that the proxiable contract assumes is being used to store the implementation
       * address.
       *
       * IMPORTANT: A proxy pointing at a proxiable contract should not be considered proxiable itself, because this risks
       * bricking a proxy that upgrades to it, by delegating to itself until out of gas. Thus it is critical that this
       * function revert if invoked through a proxy.
       */
      function proxiableUUID() external view returns (bytes32);
    }
    // SPDX-License-Identifier: MIT
    // OpenZeppelin Contracts (last updated v4.5.0) (utils/Address.sol)
    pragma solidity ^0.8.1;
    /**
     * @dev Collection of functions related to the address type
     */
    library Address {
      /**
       * @dev Returns true if `account` is a contract.
       *
       * [IMPORTANT]
       * ====
       * It is unsafe to assume that an address for which this function returns
       * false is an externally-owned account (EOA) and not a contract.
       *
       * Among others, `isContract` will return false for the following
       * types of addresses:
       *
       *  - an externally-owned account
       *  - a contract in construction
       *  - an address where a contract will be created
       *  - an address where a contract lived, but was destroyed
       * ====
       *
       * [IMPORTANT]
       * ====
       * You shouldn't rely on `isContract` to protect against flash loan attacks!
       *
       * Preventing calls from contracts is highly discouraged. It breaks composability, breaks support for smart wallets
       * like Gnosis Safe, and does not provide security since it can be circumvented by calling from a contract
       * constructor.
       * ====
       */
      function isContract(address account) internal view returns (bool) {
        // This method relies on extcodesize/address.code.length, which returns 0
        // for contracts in construction, since the code is only stored at the end
        // of the constructor execution.
        return account.code.length > 0;
      }
      /**
       * @dev Replacement for Solidity's `transfer`: sends `amount` wei to
       * `recipient`, forwarding all available gas and reverting on errors.
       *
       * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
       * of certain opcodes, possibly making contracts go over the 2300 gas limit
       * imposed by `transfer`, making them unable to receive funds via
       * `transfer`. {sendValue} removes this limitation.
       *
       * https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
       *
       * IMPORTANT: because control is transferred to `recipient`, care must be
       * taken to not create reentrancy vulnerabilities. Consider using
       * {ReentrancyGuard} or the
       * https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
       */
      function sendValue(address payable recipient, uint256 amount) internal {
        require(address(this).balance >= amount, "Address: insufficient balance");
        (bool success, ) = recipient.call{value: amount}("");
        require(
          success,
          "Address: unable to send value, recipient may have reverted"
        );
      }
      /**
       * @dev Performs a Solidity function call using a low level `call`. A
       * plain `call` is an unsafe replacement for a function call: use this
       * function instead.
       *
       * If `target` reverts with a revert reason, it is bubbled up by this
       * function (like regular Solidity function calls).
       *
       * Returns the raw returned data. To convert to the expected return value,
       * use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
       *
       * Requirements:
       *
       * - `target` must be a contract.
       * - calling `target` with `data` must not revert.
       *
       * _Available since v3.1._
       */
      function functionCall(address target, bytes memory data)
        internal
        returns (bytes memory)
      {
        return functionCall(target, data, "Address: low-level call failed");
      }
      /**
       * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with
       * `errorMessage` as a fallback revert reason when `target` reverts.
       *
       * _Available since v3.1._
       */
      function functionCall(
        address target,
        bytes memory data,
        string memory errorMessage
      ) internal returns (bytes memory) {
        return functionCallWithValue(target, data, 0, errorMessage);
      }
      /**
       * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
       * but also transferring `value` wei to `target`.
       *
       * Requirements:
       *
       * - the calling contract must have an ETH balance of at least `value`.
       * - the called Solidity function must be `payable`.
       *
       * _Available since v3.1._
       */
      function functionCallWithValue(
        address target,
        bytes memory data,
        uint256 value
      ) internal returns (bytes memory) {
        return
          functionCallWithValue(
            target,
            data,
            value,
            "Address: low-level call with value failed"
          );
      }
      /**
       * @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
       * with `errorMessage` as a fallback revert reason when `target` reverts.
       *
       * _Available since v3.1._
       */
      function functionCallWithValue(
        address target,
        bytes memory data,
        uint256 value,
        string memory errorMessage
      ) internal returns (bytes memory) {
        require(
          address(this).balance >= value,
          "Address: insufficient balance for call"
        );
        require(isContract(target), "Address: call to non-contract");
        (bool success, bytes memory returndata) = target.call{value: value}(data);
        return verifyCallResult(success, returndata, errorMessage);
      }
      /**
       * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
       * but performing a static call.
       *
       * _Available since v3.3._
       */
      function functionStaticCall(address target, bytes memory data)
        internal
        view
        returns (bytes memory)
      {
        return
          functionStaticCall(target, data, "Address: low-level static call failed");
      }
      /**
       * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
       * but performing a static call.
       *
       * _Available since v3.3._
       */
      function functionStaticCall(
        address target,
        bytes memory data,
        string memory errorMessage
      ) internal view returns (bytes memory) {
        require(isContract(target), "Address: static call to non-contract");
        (bool success, bytes memory returndata) = target.staticcall(data);
        return verifyCallResult(success, returndata, errorMessage);
      }
      /**
       * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
       * but performing a delegate call.
       *
       * _Available since v3.4._
       */
      function functionDelegateCall(address target, bytes memory data)
        internal
        returns (bytes memory)
      {
        return
          functionDelegateCall(
            target,
            data,
            "Address: low-level delegate call failed"
          );
      }
      /**
       * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
       * but performing a delegate call.
       *
       * _Available since v3.4._
       */
      function functionDelegateCall(
        address target,
        bytes memory data,
        string memory errorMessage
      ) internal returns (bytes memory) {
        require(isContract(target), "Address: delegate call to non-contract");
        (bool success, bytes memory returndata) = target.delegatecall(data);
        return verifyCallResult(success, returndata, errorMessage);
      }
      /**
       * @dev Tool to verifies that a low level call was successful, and revert if it wasn't, either by bubbling the
       * revert reason using the provided one.
       *
       * _Available since v4.3._
       */
      function verifyCallResult(
        bool success,
        bytes memory returndata,
        string memory errorMessage
      ) internal pure returns (bytes memory) {
        if (success) {
          return returndata;
        } else {
          // Look for revert reason and bubble it up if present
          if (returndata.length > 0) {
            // The easiest way to bubble the revert reason is using memory via assembly
            assembly {
              let returndata_size := mload(returndata)
              revert(add(32, returndata), returndata_size)
            }
          } else {
            revert(errorMessage);
          }
        }
      }
    }
    // SPDX-License-Identifier: MIT
    // OpenZeppelin Contracts v4.4.1 (utils/StorageSlot.sol)
    pragma solidity ^0.8.0;
    /**
     * @dev Library for reading and writing primitive types to specific storage slots.
     *
     * Storage slots are often used to avoid storage conflict when dealing with upgradeable contracts.
     * This library helps with reading and writing to such slots without the need for inline assembly.
     *
     * The functions in this library return Slot structs that contain a `value` member that can be used to read or write.
     *
     * Example usage to set ERC1967 implementation slot:
     * ```
     * contract ERC1967 {
     *     bytes32 internal constant _IMPLEMENTATION_SLOT = 0x360894a13ba1a3210667c828492db98dca3e2076cc3735a920a3ca505d382bbc;
     *
     *     function _getImplementation() internal view returns (address) {
     *         return StorageSlot.getAddressSlot(_IMPLEMENTATION_SLOT).value;
     *     }
     *
     *     function _setImplementation(address newImplementation) internal {
     *         require(Address.isContract(newImplementation), "ERC1967: new implementation is not a contract");
     *         StorageSlot.getAddressSlot(_IMPLEMENTATION_SLOT).value = newImplementation;
     *     }
     * }
     * ```
     *
     * _Available since v4.1 for `address`, `bool`, `bytes32`, and `uint256`._
     */
    library StorageSlot {
      struct AddressSlot {
        address value;
      }
      struct BooleanSlot {
        bool value;
      }
      struct Bytes32Slot {
        bytes32 value;
      }
      struct Uint256Slot {
        uint256 value;
      }
      /**
       * @dev Returns an `AddressSlot` with member `value` located at `slot`.
       */
      function getAddressSlot(bytes32 slot)
        internal
        pure
        returns (AddressSlot storage r)
      {
        assembly {
          r.slot := slot
        }
      }
      /**
       * @dev Returns an `BooleanSlot` with member `value` located at `slot`.
       */
      function getBooleanSlot(bytes32 slot)
        internal
        pure
        returns (BooleanSlot storage r)
      {
        assembly {
          r.slot := slot
        }
      }
      /**
       * @dev Returns an `Bytes32Slot` with member `value` located at `slot`.
       */
      function getBytes32Slot(bytes32 slot)
        internal
        pure
        returns (Bytes32Slot storage r)
      {
        assembly {
          r.slot := slot
        }
      }
      /**
       * @dev Returns an `Uint256Slot` with member `value` located at `slot`.
       */
      function getUint256Slot(bytes32 slot)
        internal
        pure
        returns (Uint256Slot storage r)
      {
        assembly {
          r.slot := slot
        }
      }
    }
    

    File 2 of 2: USDon
    /**SPDX-License-Identifier: BUSL-1.1
          ▄▄█████████▄
       ╓██▀└ ,╓▄▄▄, '▀██▄
      ██▀ ▄██▀▀╙╙▀▀██▄ └██µ           ,,       ,,      ,     ,,,            ,,,
     ██ ,██¬ ▄████▄  ▀█▄ ╙█▄      ▄███▀▀███▄   ███▄    ██  ███▀▀▀███▄    ▄███▀▀███,
    ██  ██ ╒█▀'   ╙█▌ ╙█▌ ██     ▐██      ███  █████,  ██  ██▌    └██▌  ██▌     └██▌
    ██ ▐█▌ ██      ╟█  █▌ ╟█     ██▌      ▐██  ██ └███ ██  ██▌     ╟██ j██       ╟██
    ╟█  ██ ╙██    ▄█▀ ▐█▌ ██     ╙██      ██▌  ██   ╙████  ██▌    ▄██▀  ██▌     ,██▀
     ██ "██, ╙▀▀███████████⌐      ╙████████▀   ██     ╙██  ███████▀▀     ╙███████▀`
      ██▄ ╙▀██▄▄▄▄▄,,,                ¬─                                    '─¬
       ╙▀██▄ '╙╙╙▀▀▀▀▀▀▀▀
          ╙▀▀██████R⌐
     */
    pragma solidity 0.8.16;
    import "contracts/external/openzeppelin/contracts-upgradeable/token/ERC20/ERC20PresetMinterPauserUpgradeable.sol";
    import "contracts/globalMarkets/gmTokenCompliance/OndoComplianceGMClientUpgradeable.sol";
    /**
     * @title  USDon
     * @author Ondo Finance
     * @notice Ondo USD (USDon) token implementation with compliance features
     *         The token supports minting, burning, pausing, and can be configured with custom name/symbol.
     */
    contract USDon is
      ERC20PresetMinterPauserUpgradeable,
      OndoComplianceGMClientUpgradeable
    {
      /// Role for changing the token name, symbol, and compliance
      bytes32 public constant CONFIGURER_ROLE = keccak256("CONFIGURER_ROLE");
      /// Role for burning tokens
      bytes32 public constant BURNER_ROLE = keccak256("BURNER_ROLE");
      /// Role for unpausing the contract
      bytes32 public constant UNPAUSER_ROLE = keccak256("UNPAUSER_ROLE");
      /// Override for the name allowing the name to be changed
      string private nameOverride;
      /// Override for the symbol allowing the symbol to be changed
      string private symbolOverride;
      /**
       * @notice Emitted when the token symbol is changed
       * @param  oldSymbol The old token symbol
       * @param  newSymbol The new token symbol
       */
      event SymbolChanged(string oldSymbol, string newSymbol);
      /**
       * @notice Emitted when the token name is changed
       * @param  oldName The old token name
       * @param  newName The new token name
       */
      event NameChanged(string oldName, string newName);
      /// @custom:oz-upgrades-unsafe-allow constructor
      constructor() {
        _disableInitializers();
      }
      /**
       * @notice Initializes the USDon contract
       * @param  _nameOverride   The initial name of the token
       * @param  _symbolOverride The initial symbol of the token
       * @param  _compliance     The address of the compliance contract
       * @dev    This function can only be called once during deployment via the proxy pattern
       */
      function initialize(
        string memory _nameOverride,
        string memory _symbolOverride,
        address _compliance
      ) public initializer {
        __USDon_init(_nameOverride, _symbolOverride, _compliance);
      }
      /**
       * @notice Internal initialization function for USDon
       * @param  _nameOverride   The initial name of the token
       * @param  _symbolOverride The initial symbol of the token
       * @param  _compliance     The address of the compliance contract
       * @dev    Initializes all parent contracts and sets up the USDon specific state
       */
      function __USDon_init(
        string memory _nameOverride,
        string memory _symbolOverride,
        address _compliance
      ) internal onlyInitializing {
        __ERC20PresetMinterPauser_init(_nameOverride, _symbolOverride);
        __OndoComplianceGMClientInitializable_init(_compliance);
        __USDon_init_unchained(_nameOverride, _symbolOverride);
      }
      /**
       * @notice Unchained initialization function for USDon-specific state
       * @param  _nameOverride   The initial name of the token
       * @param  _symbolOverride The initial symbol of the token
       * @dev    Sets up USDon-specific state without calling parent initializers
       */
      function __USDon_init_unchained(
        string memory _nameOverride,
        string memory _symbolOverride
      ) internal onlyInitializing {
        nameOverride = _nameOverride;
        symbolOverride = _symbolOverride;
      }
      /**
       * @notice Returns the name of the token
       * @dev    Overrides the default ERC20 name function to return the `nameOverride` variable,
       *         allowing the name to be changed after deployment
       */
      function name() public view virtual override returns (string memory) {
        return nameOverride;
      }
      /**
       * @notice Returns the ticker symbol of the token
       * @dev    Overrides the default ERC20 symbol function to return the `symbolOverride` variable,
       *         allowing the symbol to be changed after deployment
       */
      function symbol() public view virtual override returns (string memory) {
        return symbolOverride;
      }
      /**
       * @notice Sets the token name
       * @param  _nameOverride New token name
       */
      function setName(
        string memory _nameOverride
      ) external onlyRole(CONFIGURER_ROLE) {
        emit NameChanged(nameOverride, _nameOverride);
        nameOverride = _nameOverride;
      }
      /**
       * @notice Sets the token symbol
       * @param  _symbolOverride New token symbol
       */
      function setSymbol(
        string memory _symbolOverride
      ) external onlyRole(CONFIGURER_ROLE) {
        emit SymbolChanged(symbolOverride, _symbolOverride);
        symbolOverride = _symbolOverride;
      }
      /**
       * @notice Sets the compliance address
       * @param  _compliance New compliance address
       */
      function setCompliance(
        address _compliance
      ) external onlyRole(CONFIGURER_ROLE) {
        _setCompliance(_compliance);
      }
      /**
       * @notice Hook that is called before any transfer of tokens
       * @param  from   The address tokens are transferred from (0x0 for minting)
       * @param  to     The address tokens are transferred to (0x0 for burning)
       * @param  amount The amount of tokens being transferred
       * @dev    Validates compliance for all parties involved in the transfer
       */
      function _beforeTokenTransfer(
        address from,
        address to,
        uint256 amount
      ) internal override {
        super._beforeTokenTransfer(from, to, amount);
        // Check constraints when `transferFrom` is called to facilitate
        // a transfer between two parties that are not `from` or `to`.
        if (from != msg.sender && to != msg.sender) {
          _checkIsCompliant(msg.sender);
        }
        if (from != address(0)) {
          // If not minting
          _checkIsCompliant(from);
        }
        if (to != address(0)) {
          // If not burning
          _checkIsCompliant(to);
        }
      }
      /**
       * @notice Burns a specific amount of tokens
       * @param  from   The account whose tokens will be burned
       * @param  amount The amount of token to be burned
       * @dev    This function can be considered an admin-burn and is only callable
       *         by an address with the `BURNER_ROLE`
       */
      function burn(address from, uint256 amount) external onlyRole(BURNER_ROLE) {
        _burn(from, amount);
      }
      /**
       * @notice Unpauses the contract
       * @dev    There is already an unpause function defined in ERC20PresetMinterPauserUpgradeable, however it
       *         checks for the PAUSER_ROLE. By overriding this function, we only allow the UNPAUSER_ROLE to unpause
       *         the contract as it will have a higher threshold of trust.
       */
      function unpause() public override onlyRole(UNPAUSER_ROLE) {
        _unpause();
      }
    }
    // SPDX-License-Identifier: MIT
    // OpenZeppelin Contracts (last updated v4.5.0) (token/ERC20/presets/ERC20PresetMinterPauser.sol)
    pragma solidity ^0.8.0;
    import "contracts/external/openzeppelin/contracts-upgradeable/token/ERC20/ERC20Upgradeable.sol";
    import "contracts/external/openzeppelin/contracts-upgradeable/token/ERC20/ERC20BurnableUpgradeable.sol";
    import "contracts/external/openzeppelin/contracts-upgradeable/token/ERC20/ERC20PausableUpgradeable.sol";
    import "contracts/external/openzeppelin/contracts-upgradeable/access/AccessControlEnumerableUpgradeable.sol";
    import "contracts/external/openzeppelin/contracts-upgradeable/utils/ContextUpgradeable.sol";
    import "contracts/external/openzeppelin/contracts-upgradeable/proxy/Initializable.sol";
    /**
     * @dev {ERC20} token, including:
     *
     *  - ability for holders to burn (destroy) their tokens
     *  - a minter role that allows for token minting (creation)
     *  - a pauser role that allows to stop all token transfers
     *
     * This contract uses {AccessControl} to lock permissioned functions using the
     * different roles - head to its documentation for details.
     *
     * The account that deploys the contract will be granted the minter and pauser
     * roles, as well as the default admin role, which will let it grant both minter
     * and pauser roles to other accounts.
     *
     * _Deprecated in favor of https://wizard.openzeppelin.com/[Contracts Wizard]._
     */
    contract ERC20PresetMinterPauserUpgradeable is
      Initializable,
      ContextUpgradeable,
      AccessControlEnumerableUpgradeable,
      ERC20BurnableUpgradeable,
      ERC20PausableUpgradeable
    {
      function initialize(string memory name, string memory symbol)
        public
        virtual
        initializer
      {
        __ERC20PresetMinterPauser_init(name, symbol);
      }
      bytes32 public constant MINTER_ROLE = keccak256("MINTER_ROLE");
      bytes32 public constant PAUSER_ROLE = keccak256("PAUSER_ROLE");
      /**
       * @dev Grants `DEFAULT_ADMIN_ROLE`, `MINTER_ROLE` and `PAUSER_ROLE` to the
       * account that deploys the contract.
       *
       * See {ERC20-constructor}.
       */
      function __ERC20PresetMinterPauser_init(
        string memory name,
        string memory symbol
      ) internal onlyInitializing {
        __ERC20_init_unchained(name, symbol);
        __Pausable_init_unchained();
        __ERC20PresetMinterPauser_init_unchained(name, symbol);
      }
      function __ERC20PresetMinterPauser_init_unchained(
        string memory,
        string memory
      ) internal onlyInitializing {
        _setupRole(DEFAULT_ADMIN_ROLE, _msgSender());
        _setupRole(MINTER_ROLE, _msgSender());
        _setupRole(PAUSER_ROLE, _msgSender());
      }
      /**
       * @dev Creates `amount` new tokens for `to`.
       *
       * See {ERC20-_mint}.
       *
       * Requirements:
       *
       * - the caller must have the `MINTER_ROLE`.
       */
      function mint(address to, uint256 amount) public virtual {
        require(
          hasRole(MINTER_ROLE, _msgSender()),
          "ERC20PresetMinterPauser: must have minter role to mint"
        );
        _mint(to, amount);
      }
      /**
       * @dev Pauses all token transfers.
       *
       * See {ERC20Pausable} and {Pausable-_pause}.
       *
       * Requirements:
       *
       * - the caller must have the `PAUSER_ROLE`.
       */
      function pause() public virtual {
        require(
          hasRole(PAUSER_ROLE, _msgSender()),
          "ERC20PresetMinterPauser: must have pauser role to pause"
        );
        _pause();
      }
      /**
       * @dev Unpauses all token transfers.
       *
       * See {ERC20Pausable} and {Pausable-_unpause}.
       *
       * Requirements:
       *
       * - the caller must have the `PAUSER_ROLE`.
       */
      function unpause() public virtual {
        require(
          hasRole(PAUSER_ROLE, _msgSender()),
          "ERC20PresetMinterPauser: must have pauser role to unpause"
        );
        _unpause();
      }
      function _beforeTokenTransfer(
        address from,
        address to,
        uint256 amount
      ) internal virtual override(ERC20Upgradeable, ERC20PausableUpgradeable) {
        super._beforeTokenTransfer(from, to, amount);
      }
      /**
       * @dev This empty reserved space is put in place to allow future versions to add new
       * variables without shifting down storage in the inheritance chain.
       * See https://docs.openzeppelin.com/contracts/4.x/upgradeable#storage_gaps
       */
      uint256[50] private __gap;
    }
    /**SPDX-License-Identifier: BUSL-1.1
          ▄▄█████████▄
       ╓██▀└ ,╓▄▄▄, '▀██▄
      ██▀ ▄██▀▀╙╙▀▀██▄ └██µ           ,,       ,,      ,     ,,,            ,,,
     ██ ,██¬ ▄████▄  ▀█▄ ╙█▄      ▄███▀▀███▄   ███▄    ██  ███▀▀▀███▄    ▄███▀▀███,
    ██  ██ ╒█▀'   ╙█▌ ╙█▌ ██     ▐██      ███  █████,  ██  ██▌    └██▌  ██▌     └██▌
    ██ ▐█▌ ██      ╟█  █▌ ╟█     ██▌      ▐██  ██ └███ ██  ██▌     ╟██ j██       ╟██
    ╟█  ██ ╙██    ▄█▀ ▐█▌ ██     ╙██      ██▌  ██   ╙████  ██▌    ▄██▀  ██▌     ,██▀
     ██ "██, ╙▀▀███████████⌐      ╙████████▀   ██     ╙██  ███████▀▀     ╙███████▀`
      ██▄ ╙▀██▄▄▄▄▄,,,                ¬─                                    '─¬
       ╙▀██▄ '╙╙╙▀▀▀▀▀▀▀▀
          ╙▀▀██████R⌐
     */
    pragma solidity 0.8.16;
    import "contracts/external/openzeppelin/contracts-upgradeable/proxy/Initializable.sol";
    import "contracts/globalMarkets/gmTokenCompliance/IOndoComplianceGMView.sol";
    /**
     * @title  ComplianceClient
     * @author Ondo Finance
     * @notice This abstract contract manages state for upgradeable compliance
     *         clients
     */
    abstract contract OndoComplianceGMClientUpgradeable is Initializable {
      /// Compliance contract
      IOndoComplianceGMView public compliance;
      /**
       * @notice Emitted when the compliance address is set
       * @param  oldCompliance The old compliance address
       * @param  newCompliance The new compliance address
       */
      event ComplianceSet(
        address indexed oldCompliance,
        address indexed newCompliance
      );
      /// Error emitted when the compliance address is zero
      error ComplianceZeroAddress();
      /**
       * @notice Initialize the contract by setting compliance variable
       *
       * @param  _compliance Address of the compliance contract
       *
       * @dev    Function should be called by the inheriting contract on
       *         initialization
       */
      function __OndoComplianceGMClientInitializable_init(
        address _compliance
      ) internal onlyInitializing {
        __OndoComplianceGMClientInitializable_init_unchained(_compliance);
      }
      /**
       * @dev Internal function to future-proof parent linearization. Matches OZ
       *      upgradeable suggestions
       */
      function __OndoComplianceGMClientInitializable_init_unchained(
        address _compliance
      ) internal onlyInitializing {
        _setCompliance(_compliance);
      }
      /**
       * @notice Sets the compliance address for this client
       * @param  _compliance The new compliance address
       */
      function _setCompliance(address _compliance) internal {
        if (_compliance == address(0)) {
          revert ComplianceZeroAddress();
        }
        address oldCompliance = address(compliance);
        compliance = IOndoComplianceGMView(_compliance);
        emit ComplianceSet(oldCompliance, _compliance);
      }
      /**
       * @notice Checks whether an address has been blocked
       * @param  account The account to check
       * @dev    This function will revert if the account is not compliant
       */
      function _checkIsCompliant(address account) internal {
        compliance.checkIsCompliant(account);
      }
      /**
       * @dev This empty reserved space is put in place to allow future versions to add new
       * variables without shifting down storage in the inheritance chain.
       * See https://docs.openzeppelin.com/contracts/4.x/upgradeable#storage_gaps
       */
      uint256[49] private __gap;
    }
    // SPDX-License-Identifier: MIT
    // OpenZeppelin Contracts (last updated v4.7.0) (token/ERC20/ERC20.sol)
    pragma solidity ^0.8.0;
    import "contracts/external/openzeppelin/contracts-upgradeable/token/ERC20/IERC20Upgradeable.sol";
    import "contracts/external/openzeppelin/contracts-upgradeable/token/ERC20/IERC20MetadataUpgradeable.sol";
    import "contracts/external/openzeppelin/contracts-upgradeable/utils/ContextUpgradeable.sol";
    import "contracts/external/openzeppelin/contracts-upgradeable/proxy/Initializable.sol";
    /**
     * @dev Implementation of the {IERC20} interface.
     *
     * This implementation is agnostic to the way tokens are created. This means
     * that a supply mechanism has to be added in a derived contract using {_mint}.
     * For a generic mechanism see {ERC20PresetMinterPauser}.
     *
     * TIP: For a detailed writeup see our guide
     * https://forum.zeppelin.solutions/t/how-to-implement-erc20-supply-mechanisms/226[How
     * to implement supply mechanisms].
     *
     * We have followed general OpenZeppelin Contracts guidelines: functions revert
     * instead returning `false` on failure. This behavior is nonetheless
     * conventional and does not conflict with the expectations of ERC20
     * applications.
     *
     * Additionally, an {Approval} event is emitted on calls to {transferFrom}.
     * This allows applications to reconstruct the allowance for all accounts just
     * by listening to said events. Other implementations of the EIP may not emit
     * these events, as it isn't required by the specification.
     *
     * Finally, the non-standard {decreaseAllowance} and {increaseAllowance}
     * functions have been added to mitigate the well-known issues around setting
     * allowances. See {IERC20-approve}.
     */
    contract ERC20Upgradeable is
      Initializable,
      ContextUpgradeable,
      IERC20Upgradeable,
      IERC20MetadataUpgradeable
    {
      mapping(address => uint256) private _balances;
      mapping(address => mapping(address => uint256)) private _allowances;
      uint256 private _totalSupply;
      string private _name;
      string private _symbol;
      /**
       * @dev Sets the values for {name} and {symbol}.
       *
       * The default value of {decimals} is 18. To select a different value for
       * {decimals} you should overload it.
       *
       * All two of these values are immutable: they can only be set once during
       * construction.
       */
      function __ERC20_init(string memory name_, string memory symbol_)
        internal
        onlyInitializing
      {
        __ERC20_init_unchained(name_, symbol_);
      }
      function __ERC20_init_unchained(string memory name_, string memory symbol_)
        internal
        onlyInitializing
      {
        _name = name_;
        _symbol = symbol_;
      }
      /**
       * @dev Returns the name of the token.
       */
      function name() public view virtual override returns (string memory) {
        return _name;
      }
      /**
       * @dev Returns the symbol of the token, usually a shorter version of the
       * name.
       */
      function symbol() public view virtual override returns (string memory) {
        return _symbol;
      }
      /**
       * @dev Returns the number of decimals used to get its user representation.
       * For example, if `decimals` equals `2`, a balance of `505` tokens should
       * be displayed to a user as `5.05` (`505 / 10 ** 2`).
       *
       * Tokens usually opt for a value of 18, imitating the relationship between
       * Ether and Wei. This is the value {ERC20} uses, unless this function is
       * overridden;
       *
       * NOTE: This information is only used for _display_ purposes: it in
       * no way affects any of the arithmetic of the contract, including
       * {IERC20-balanceOf} and {IERC20-transfer}.
       */
      function decimals() public view virtual override returns (uint8) {
        return 18;
      }
      /**
       * @dev See {IERC20-totalSupply}.
       */
      function totalSupply() public view virtual override returns (uint256) {
        return _totalSupply;
      }
      /**
       * @dev See {IERC20-balanceOf}.
       */
      function balanceOf(address account)
        public
        view
        virtual
        override
        returns (uint256)
      {
        return _balances[account];
      }
      /**
       * @dev See {IERC20-transfer}.
       *
       * Requirements:
       *
       * - `to` cannot be the zero address.
       * - the caller must have a balance of at least `amount`.
       */
      function transfer(address to, uint256 amount)
        public
        virtual
        override
        returns (bool)
      {
        address owner = _msgSender();
        _transfer(owner, to, amount);
        return true;
      }
      /**
       * @dev See {IERC20-allowance}.
       */
      function allowance(address owner, address spender)
        public
        view
        virtual
        override
        returns (uint256)
      {
        return _allowances[owner][spender];
      }
      /**
       * @dev See {IERC20-approve}.
       *
       * NOTE: If `amount` is the maximum `uint256`, the allowance is not updated on
       * `transferFrom`. This is semantically equivalent to an infinite approval.
       *
       * Requirements:
       *
       * - `spender` cannot be the zero address.
       */
      function approve(address spender, uint256 amount)
        public
        virtual
        override
        returns (bool)
      {
        address owner = _msgSender();
        _approve(owner, spender, amount);
        return true;
      }
      /**
       * @dev See {IERC20-transferFrom}.
       *
       * Emits an {Approval} event indicating the updated allowance. This is not
       * required by the EIP. See the note at the beginning of {ERC20}.
       *
       * NOTE: Does not update the allowance if the current allowance
       * is the maximum `uint256`.
       *
       * Requirements:
       *
       * - `from` and `to` cannot be the zero address.
       * - `from` must have a balance of at least `amount`.
       * - the caller must have allowance for ``from``'s tokens of at least
       * `amount`.
       */
      function transferFrom(
        address from,
        address to,
        uint256 amount
      ) public virtual override returns (bool) {
        address spender = _msgSender();
        _spendAllowance(from, spender, amount);
        _transfer(from, to, amount);
        return true;
      }
      /**
       * @dev Atomically increases the allowance granted to `spender` by the caller.
       *
       * This is an alternative to {approve} that can be used as a mitigation for
       * problems described in {IERC20-approve}.
       *
       * Emits an {Approval} event indicating the updated allowance.
       *
       * Requirements:
       *
       * - `spender` cannot be the zero address.
       */
      function increaseAllowance(address spender, uint256 addedValue)
        public
        virtual
        returns (bool)
      {
        address owner = _msgSender();
        _approve(owner, spender, allowance(owner, spender) + addedValue);
        return true;
      }
      /**
       * @dev Atomically decreases the allowance granted to `spender` by the caller.
       *
       * This is an alternative to {approve} that can be used as a mitigation for
       * problems described in {IERC20-approve}.
       *
       * Emits an {Approval} event indicating the updated allowance.
       *
       * Requirements:
       *
       * - `spender` cannot be the zero address.
       * - `spender` must have allowance for the caller of at least
       * `subtractedValue`.
       */
      function decreaseAllowance(address spender, uint256 subtractedValue)
        public
        virtual
        returns (bool)
      {
        address owner = _msgSender();
        uint256 currentAllowance = allowance(owner, spender);
        require(
          currentAllowance >= subtractedValue,
          "ERC20: decreased allowance below zero"
        );
        unchecked {
          _approve(owner, spender, currentAllowance - subtractedValue);
        }
        return true;
      }
      /**
       * @dev Moves `amount` of tokens from `from` to `to`.
       *
       * This internal function is equivalent to {transfer}, and can be used to
       * e.g. implement automatic token fees, slashing mechanisms, etc.
       *
       * Emits a {Transfer} event.
       *
       * Requirements:
       *
       * - `from` cannot be the zero address.
       * - `to` cannot be the zero address.
       * - `from` must have a balance of at least `amount`.
       */
      function _transfer(
        address from,
        address to,
        uint256 amount
      ) internal virtual {
        require(from != address(0), "ERC20: transfer from the zero address");
        require(to != address(0), "ERC20: transfer to the zero address");
        _beforeTokenTransfer(from, to, amount);
        uint256 fromBalance = _balances[from];
        require(fromBalance >= amount, "ERC20: transfer amount exceeds balance");
        unchecked {
          _balances[from] = fromBalance - amount;
        }
        _balances[to] += amount;
        emit Transfer(from, to, amount);
        _afterTokenTransfer(from, to, amount);
      }
      /** @dev Creates `amount` tokens and assigns them to `account`, increasing
       * the total supply.
       *
       * Emits a {Transfer} event with `from` set to the zero address.
       *
       * Requirements:
       *
       * - `account` cannot be the zero address.
       */
      function _mint(address account, uint256 amount) internal virtual {
        require(account != address(0), "ERC20: mint to the zero address");
        _beforeTokenTransfer(address(0), account, amount);
        _totalSupply += amount;
        _balances[account] += amount;
        emit Transfer(address(0), account, amount);
        _afterTokenTransfer(address(0), account, amount);
      }
      /**
       * @dev Destroys `amount` tokens from `account`, reducing the
       * total supply.
       *
       * Emits a {Transfer} event with `to` set to the zero address.
       *
       * Requirements:
       *
       * - `account` cannot be the zero address.
       * - `account` must have at least `amount` tokens.
       */
      function _burn(address account, uint256 amount) internal virtual {
        require(account != address(0), "ERC20: burn from the zero address");
        _beforeTokenTransfer(account, address(0), amount);
        uint256 accountBalance = _balances[account];
        require(accountBalance >= amount, "ERC20: burn amount exceeds balance");
        unchecked {
          _balances[account] = accountBalance - amount;
        }
        _totalSupply -= amount;
        emit Transfer(account, address(0), amount);
        _afterTokenTransfer(account, address(0), amount);
      }
      /**
       * @dev Sets `amount` as the allowance of `spender` over the `owner` s tokens.
       *
       * This internal function is equivalent to `approve`, and can be used to
       * e.g. set automatic allowances for certain subsystems, etc.
       *
       * Emits an {Approval} event.
       *
       * Requirements:
       *
       * - `owner` cannot be the zero address.
       * - `spender` cannot be the zero address.
       */
      function _approve(
        address owner,
        address spender,
        uint256 amount
      ) internal virtual {
        require(owner != address(0), "ERC20: approve from the zero address");
        require(spender != address(0), "ERC20: approve to the zero address");
        _allowances[owner][spender] = amount;
        emit Approval(owner, spender, amount);
      }
      /**
       * @dev Updates `owner` s allowance for `spender` based on spent `amount`.
       *
       * Does not update the allowance amount in case of infinite allowance.
       * Revert if not enough allowance is available.
       *
       * Might emit an {Approval} event.
       */
      function _spendAllowance(
        address owner,
        address spender,
        uint256 amount
      ) internal virtual {
        uint256 currentAllowance = allowance(owner, spender);
        if (currentAllowance != type(uint256).max) {
          require(currentAllowance >= amount, "ERC20: insufficient allowance");
          unchecked {
            _approve(owner, spender, currentAllowance - amount);
          }
        }
      }
      /**
       * @dev Hook that is called before any transfer of tokens. This includes
       * minting and burning.
       *
       * Calling conditions:
       *
       * - when `from` and `to` are both non-zero, `amount` of ``from``'s tokens
       * will be transferred to `to`.
       * - when `from` is zero, `amount` tokens will be minted for `to`.
       * - when `to` is zero, `amount` of ``from``'s tokens will be burned.
       * - `from` and `to` are never both zero.
       *
       * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
       */
      function _beforeTokenTransfer(
        address from,
        address to,
        uint256 amount
      ) internal virtual {}
      /**
       * @dev Hook that is called after any transfer of tokens. This includes
       * minting and burning.
       *
       * Calling conditions:
       *
       * - when `from` and `to` are both non-zero, `amount` of ``from``'s tokens
       * has been transferred to `to`.
       * - when `from` is zero, `amount` tokens have been minted for `to`.
       * - when `to` is zero, `amount` of ``from``'s tokens have been burned.
       * - `from` and `to` are never both zero.
       *
       * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
       */
      function _afterTokenTransfer(
        address from,
        address to,
        uint256 amount
      ) internal virtual {}
      /**
       * @dev This empty reserved space is put in place to allow future versions to add new
       * variables without shifting down storage in the inheritance chain.
       * See https://docs.openzeppelin.com/contracts/4.x/upgradeable#storage_gaps
       */
      uint256[45] private __gap;
    }
    // SPDX-License-Identifier: MIT
    // OpenZeppelin Contracts (last updated v4.5.0) (token/ERC20/extensions/ERC20Burnable.sol)
    pragma solidity ^0.8.0;
    import "contracts/external/openzeppelin/contracts-upgradeable/token/ERC20/ERC20Upgradeable.sol";
    import "contracts/external/openzeppelin/contracts-upgradeable/utils/ContextUpgradeable.sol";
    import "contracts/external/openzeppelin/contracts-upgradeable/proxy/Initializable.sol";
    /**
     * @dev Extension of {ERC20} that allows token holders to destroy both their own
     * tokens and those that they have an allowance for, in a way that can be
     * recognized off-chain (via event analysis).
     */
    abstract contract ERC20BurnableUpgradeable is
      Initializable,
      ContextUpgradeable,
      ERC20Upgradeable
    {
      function __ERC20Burnable_init() internal onlyInitializing {}
      function __ERC20Burnable_init_unchained() internal onlyInitializing {}
      /**
       * @dev Destroys `amount` tokens from the caller.
       *
       * See {ERC20-_burn}.
       */
      function burn(uint256 amount) public virtual {
        _burn(_msgSender(), amount);
      }
      /**
       * @dev Destroys `amount` tokens from `account`, deducting from the caller's
       * allowance.
       *
       * See {ERC20-_burn} and {ERC20-allowance}.
       *
       * Requirements:
       *
       * - the caller must have allowance for ``accounts``'s tokens of at least
       * `amount`.
       */
      function burnFrom(address account, uint256 amount) public virtual {
        _spendAllowance(account, _msgSender(), amount);
        _burn(account, amount);
      }
      /**
       * @dev This empty reserved space is put in place to allow future versions to add new
       * variables without shifting down storage in the inheritance chain.
       * See https://docs.openzeppelin.com/contracts/4.x/upgradeable#storage_gaps
       */
      uint256[50] private __gap;
    }
    // SPDX-License-Identifier: MIT
    // OpenZeppelin Contracts v4.4.1 (token/ERC20/extensions/ERC20Pausable.sol)
    pragma solidity ^0.8.0;
    import "contracts/external/openzeppelin/contracts-upgradeable/token/ERC20/ERC20Upgradeable.sol";
    import "contracts/external/openzeppelin/contracts-upgradeable/security/PausableUpgradeable.sol";
    import "contracts/external/openzeppelin/contracts-upgradeable/proxy/Initializable.sol";
    /**
     * @dev ERC20 token with pausable token transfers, minting and burning.
     *
     * Useful for scenarios such as preventing trades until the end of an evaluation
     * period, or having an emergency switch for freezing all token transfers in the
     * event of a large bug.
     */
    abstract contract ERC20PausableUpgradeable is
      Initializable,
      ERC20Upgradeable,
      PausableUpgradeable
    {
      function __ERC20Pausable_init() internal onlyInitializing {
        __Pausable_init_unchained();
      }
      function __ERC20Pausable_init_unchained() internal onlyInitializing {}
      /**
       * @dev See {ERC20-_beforeTokenTransfer}.
       *
       * Requirements:
       *
       * - the contract must not be paused.
       */
      function _beforeTokenTransfer(
        address from,
        address to,
        uint256 amount
      ) internal virtual override {
        super._beforeTokenTransfer(from, to, amount);
        require(!paused(), "ERC20Pausable: token transfer while paused");
      }
      /**
       * @dev This empty reserved space is put in place to allow future versions to add new
       * variables without shifting down storage in the inheritance chain.
       * See https://docs.openzeppelin.com/contracts/4.x/upgradeable#storage_gaps
       */
      uint256[50] private __gap;
    }
    // SPDX-License-Identifier: MIT
    // OpenZeppelin Contracts (last updated v4.5.0) (access/AccessControlEnumerable.sol)
    pragma solidity ^0.8.0;
    import "contracts/external/openzeppelin/contracts-upgradeable/access/IAccessControlEnumerableUpgradeable.sol";
    import "contracts/external/openzeppelin/contracts-upgradeable/access/AccessControlUpgradeable.sol";
    import "contracts/external/openzeppelin/contracts-upgradeable/utils/EnumerableSetUpgradeable.sol";
    import "contracts/external/openzeppelin/contracts-upgradeable/proxy/Initializable.sol";
    /**
     * @dev Extension of {AccessControl} that allows enumerating the members of each role.
     */
    abstract contract AccessControlEnumerableUpgradeable is
      Initializable,
      IAccessControlEnumerableUpgradeable,
      AccessControlUpgradeable
    {
      function __AccessControlEnumerable_init() internal onlyInitializing {}
      function __AccessControlEnumerable_init_unchained()
        internal
        onlyInitializing
      {}
      using EnumerableSetUpgradeable for EnumerableSetUpgradeable.AddressSet;
      mapping(bytes32 => EnumerableSetUpgradeable.AddressSet) private _roleMembers;
      /**
       * @dev See {IERC165-supportsInterface}.
       */
      function supportsInterface(bytes4 interfaceId)
        public
        view
        virtual
        override
        returns (bool)
      {
        return
          interfaceId == type(IAccessControlEnumerableUpgradeable).interfaceId ||
          super.supportsInterface(interfaceId);
      }
      /**
       * @dev Returns one of the accounts that have `role`. `index` must be a
       * value between 0 and {getRoleMemberCount}, non-inclusive.
       *
       * Role bearers are not sorted in any particular way, and their ordering may
       * change at any point.
       *
       * WARNING: When using {getRoleMember} and {getRoleMemberCount}, make sure
       * you perform all queries on the same block. See the following
       * https://forum.openzeppelin.com/t/iterating-over-elements-on-enumerableset-in-openzeppelin-contracts/2296[forum post]
       * for more information.
       */
      function getRoleMember(bytes32 role, uint256 index)
        public
        view
        virtual
        override
        returns (address)
      {
        return _roleMembers[role].at(index);
      }
      /**
       * @dev Returns the number of accounts that have `role`. Can be used
       * together with {getRoleMember} to enumerate all bearers of a role.
       */
      function getRoleMemberCount(bytes32 role)
        public
        view
        virtual
        override
        returns (uint256)
      {
        return _roleMembers[role].length();
      }
      /**
       * @dev Overload {_grantRole} to track enumerable memberships
       */
      function _grantRole(bytes32 role, address account) internal virtual override {
        super._grantRole(role, account);
        _roleMembers[role].add(account);
      }
      /**
       * @dev Overload {_revokeRole} to track enumerable memberships
       */
      function _revokeRole(bytes32 role, address account)
        internal
        virtual
        override
      {
        super._revokeRole(role, account);
        _roleMembers[role].remove(account);
      }
      /**
       * @dev This empty reserved space is put in place to allow future versions to add new
       * variables without shifting down storage in the inheritance chain.
       * See https://docs.openzeppelin.com/contracts/4.x/upgradeable#storage_gaps
       */
      uint256[49] private __gap;
    }
    // SPDX-License-Identifier: MIT
    // OpenZeppelin Contracts v4.4.1 (utils/Context.sol)
    pragma solidity ^0.8.0;
    import "contracts/external/openzeppelin/contracts-upgradeable/proxy/Initializable.sol";
    /**
     * @dev Provides information about the current execution context, including the
     * sender of the transaction and its data. While these are generally available
     * via msg.sender and msg.data, they should not be accessed in such a direct
     * manner, since when dealing with meta-transactions the account sending and
     * paying for execution may not be the actual sender (as far as an application
     * is concerned).
     *
     * This contract is only required for intermediate, library-like contracts.
     */
    abstract contract ContextUpgradeable is Initializable {
      function __Context_init() internal onlyInitializing {}
      function __Context_init_unchained() internal onlyInitializing {}
      function _msgSender() internal view virtual returns (address) {
        return msg.sender;
      }
      function _msgData() internal view virtual returns (bytes calldata) {
        return msg.data;
      }
      /**
       * @dev This empty reserved space is put in place to allow future versions to add new
       * variables without shifting down storage in the inheritance chain.
       * See https://docs.openzeppelin.com/contracts/4.x/upgradeable#storage_gaps
       */
      uint256[50] private __gap;
    }
    // SPDX-License-Identifier: MIT
    // OpenZeppelin Contracts (last updated v4.7.0) (proxy/utils/Initializable.sol)
    pragma solidity ^0.8.2;
    import "contracts/external/openzeppelin/contracts-upgradeable/utils/AddressUpgradeable.sol";
    /**
     * @dev This is a base contract to aid in writing upgradeable contracts, or any kind of contract that will be deployed
     * behind a proxy. Since proxied contracts do not make use of a constructor, it's common to move constructor logic to an
     * external initializer function, usually called `initialize`. It then becomes necessary to protect this initializer
     * function so it can only be called once. The {initializer} modifier provided by this contract will have this effect.
     *
     * The initialization functions use a version number. Once a version number is used, it is consumed and cannot be
     * reused. This mechanism prevents re-execution of each "step" but allows the creation of new initialization steps in
     * case an upgrade adds a module that needs to be initialized.
     *
     * For example:
     *
     * [.hljs-theme-light.nopadding]
     * ```
     * contract MyToken is ERC20Upgradeable {
     *     function initialize() initializer public {
     *         __ERC20_init("MyToken", "MTK");
     *     }
     * }
     * contract MyTokenV2 is MyToken, ERC20PermitUpgradeable {
     *     function initializeV2() reinitializer(2) public {
     *         __ERC20Permit_init("MyToken");
     *     }
     * }
     * ```
     *
     * TIP: To avoid leaving the proxy in an uninitialized state, the initializer function should be called as early as
     * possible by providing the encoded function call as the `_data` argument to {ERC1967Proxy-constructor}.
     *
     * CAUTION: When used with inheritance, manual care must be taken to not invoke a parent initializer twice, or to ensure
     * that all initializers are idempotent. This is not verified automatically as constructors are by Solidity.
     *
     * [CAUTION]
     * ====
     * Avoid leaving a contract uninitialized.
     *
     * An uninitialized contract can be taken over by an attacker. This applies to both a proxy and its implementation
     * contract, which may impact the proxy. To prevent the implementation contract from being used, you should invoke
     * the {_disableInitializers} function in the constructor to automatically lock it when it is deployed:
     *
     * [.hljs-theme-light.nopadding]
     * ```
     * /// @custom:oz-upgrades-unsafe-allow constructor
     * constructor() {
     *     _disableInitializers();
     * }
     * ```
     * ====
     */
    abstract contract Initializable {
      /**
       * @dev Indicates that the contract has been initialized.
       * @custom:oz-retyped-from bool
       */
      uint8 private _initialized;
      /**
       * @dev Indicates that the contract is in the process of being initialized.
       */
      bool private _initializing;
      /**
       * @dev Triggered when the contract has been initialized or reinitialized.
       */
      event Initialized(uint8 version);
      /**
       * @dev A modifier that defines a protected initializer function that can be invoked at most once. In its scope,
       * `onlyInitializing` functions can be used to initialize parent contracts. Equivalent to `reinitializer(1)`.
       */
      modifier initializer() {
        bool isTopLevelCall = !_initializing;
        require(
          (isTopLevelCall && _initialized < 1) ||
            (!AddressUpgradeable.isContract(address(this)) && _initialized == 1),
          "Initializable: contract is already initialized"
        );
        _initialized = 1;
        if (isTopLevelCall) {
          _initializing = true;
        }
        _;
        if (isTopLevelCall) {
          _initializing = false;
          emit Initialized(1);
        }
      }
      /**
       * @dev A modifier that defines a protected reinitializer function that can be invoked at most once, and only if the
       * contract hasn't been initialized to a greater version before. In its scope, `onlyInitializing` functions can be
       * used to initialize parent contracts.
       *
       * `initializer` is equivalent to `reinitializer(1)`, so a reinitializer may be used after the original
       * initialization step. This is essential to configure modules that are added through upgrades and that require
       * initialization.
       *
       * Note that versions can jump in increments greater than 1; this implies that if multiple reinitializers coexist in
       * a contract, executing them in the right order is up to the developer or operator.
       */
      modifier reinitializer(uint8 version) {
        require(
          !_initializing && _initialized < version,
          "Initializable: contract is already initialized"
        );
        _initialized = version;
        _initializing = true;
        _;
        _initializing = false;
        emit Initialized(version);
      }
      /**
       * @dev Modifier to protect an initialization function so that it can only be invoked by functions with the
       * {initializer} and {reinitializer} modifiers, directly or indirectly.
       */
      modifier onlyInitializing() {
        require(_initializing, "Initializable: contract is not initializing");
        _;
      }
      /**
       * @dev Locks the contract, preventing any future reinitialization. This cannot be part of an initializer call.
       * Calling this in the constructor of a contract will prevent that contract from being initialized or reinitialized
       * to any version. It is recommended to use this to lock implementation contracts that are designed to be called
       * through proxies.
       */
      function _disableInitializers() internal virtual {
        require(!_initializing, "Initializable: contract is initializing");
        if (_initialized < type(uint8).max) {
          _initialized = type(uint8).max;
          emit Initialized(type(uint8).max);
        }
      }
    }
    // SPDX-License-Identifier: BUSL-1.1
    /*
          ▄▄█████████▄
       ╓██▀└ ,╓▄▄▄, '▀██▄
      ██▀ ▄██▀▀╙╙▀▀██▄ └██µ           ,,       ,,      ,     ,,,            ,,,
     ██ ,██¬ ▄████▄  ▀█▄ ╙█▄      ▄███▀▀███▄   ███▄    ██  ███▀▀▀███▄    ▄███▀▀███,
    ██  ██ ╒█▀'   ╙█▌ ╙█▌ ██     ▐██      ███  █████,  ██  ██▌    └██▌  ██▌     └██▌
    ██ ▐█▌ ██      ╟█  █▌ ╟█     ██▌      ▐██  ██ └███ ██  ██▌     ╟██ j██       ╟██
    ╟█  ██ ╙██    ▄█▀ ▐█▌ ██     ╙██      ██▌  ██   ╙████  ██▌    ▄██▀  ██▌     ,██▀
     ██ "██, ╙▀▀███████████⌐      ╙████████▀   ██     ╙██  ███████▀▀     ╙███████▀`
      ██▄ ╙▀██▄▄▄▄▄,,,                ¬─                                    '─¬
       ╙▀██▄ '╙╙╙▀▀▀▀▀▀▀▀
          ╙▀▀██████R⌐
     */
    pragma solidity 0.8.16;
    /**
     * @title  IOndoComplianceGMView
     * @author Ondo Finance
     * @notice Provides an interface for compliance checks on GM tokens.
     */
    interface IOndoComplianceGMView {
      function checkIsCompliant(address user) external;
    }
    // SPDX-License-Identifier: MIT
    // OpenZeppelin Contracts (last updated v4.6.0) (token/ERC20/IERC20.sol)
    pragma solidity ^0.8.0;
    /**
     * @dev Interface of the ERC20 standard as defined in the EIP.
     */
    interface IERC20Upgradeable {
      /**
       * @dev Emitted when `value` tokens are moved from one account (`from`) to
       * another (`to`).
       *
       * Note that `value` may be zero.
       */
      event Transfer(address indexed from, address indexed to, uint256 value);
      /**
       * @dev Emitted when the allowance of a `spender` for an `owner` is set by
       * a call to {approve}. `value` is the new allowance.
       */
      event Approval(address indexed owner, address indexed spender, uint256 value);
      /**
       * @dev Returns the amount of tokens in existence.
       */
      function totalSupply() external view returns (uint256);
      /**
       * @dev Returns the amount of tokens owned by `account`.
       */
      function balanceOf(address account) external view returns (uint256);
      /**
       * @dev Moves `amount` tokens from the caller's account to `to`.
       *
       * Returns a boolean value indicating whether the operation succeeded.
       *
       * Emits a {Transfer} event.
       */
      function transfer(address to, uint256 amount) external returns (bool);
      /**
       * @dev Returns the remaining number of tokens that `spender` will be
       * allowed to spend on behalf of `owner` through {transferFrom}. This is
       * zero by default.
       *
       * This value changes when {approve} or {transferFrom} are called.
       */
      function allowance(address owner, address spender)
        external
        view
        returns (uint256);
      /**
       * @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
       *
       * Returns a boolean value indicating whether the operation succeeded.
       *
       * IMPORTANT: Beware that changing an allowance with this method brings the risk
       * that someone may use both the old and the new allowance by unfortunate
       * transaction ordering. One possible solution to mitigate this race
       * condition is to first reduce the spender's allowance to 0 and set the
       * desired value afterwards:
       * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
       *
       * Emits an {Approval} event.
       */
      function approve(address spender, uint256 amount) external returns (bool);
      /**
       * @dev Moves `amount` tokens from `from` to `to` using the
       * allowance mechanism. `amount` is then deducted from the caller's
       * allowance.
       *
       * Returns a boolean value indicating whether the operation succeeded.
       *
       * Emits a {Transfer} event.
       */
      function transferFrom(
        address from,
        address to,
        uint256 amount
      ) external returns (bool);
    }
    // SPDX-License-Identifier: MIT
    // OpenZeppelin Contracts v4.4.1 (token/ERC20/extensions/IERC20Metadata.sol)
    pragma solidity ^0.8.0;
    import "contracts/external/openzeppelin/contracts-upgradeable/token/ERC20/IERC20Upgradeable.sol";
    /**
     * @dev Interface for the optional metadata functions from the ERC20 standard.
     *
     * _Available since v4.1._
     */
    interface IERC20MetadataUpgradeable is IERC20Upgradeable {
      /**
       * @dev Returns the name of the token.
       */
      function name() external view returns (string memory);
      /**
       * @dev Returns the symbol of the token.
       */
      function symbol() external view returns (string memory);
      /**
       * @dev Returns the decimals places of the token.
       */
      function decimals() external view returns (uint8);
    }
    // SPDX-License-Identifier: MIT
    // OpenZeppelin Contracts (last updated v4.7.0) (security/Pausable.sol)
    pragma solidity ^0.8.0;
    import "contracts/external/openzeppelin/contracts-upgradeable/utils/ContextUpgradeable.sol";
    import "contracts/external/openzeppelin/contracts-upgradeable/proxy/Initializable.sol";
    /**
     * @dev Contract module which allows children to implement an emergency stop
     * mechanism that can be triggered by an authorized account.
     *
     * This module is used through inheritance. It will make available the
     * modifiers `whenNotPaused` and `whenPaused`, which can be applied to
     * the functions of your contract. Note that they will not be pausable by
     * simply including this module, only once the modifiers are put in place.
     */
    abstract contract PausableUpgradeable is Initializable, ContextUpgradeable {
      /**
       * @dev Emitted when the pause is triggered by `account`.
       */
      event Paused(address account);
      /**
       * @dev Emitted when the pause is lifted by `account`.
       */
      event Unpaused(address account);
      bool private _paused;
      /**
       * @dev Initializes the contract in unpaused state.
       */
      function __Pausable_init() internal onlyInitializing {
        __Pausable_init_unchained();
      }
      function __Pausable_init_unchained() internal onlyInitializing {
        _paused = false;
      }
      /**
       * @dev Modifier to make a function callable only when the contract is not paused.
       *
       * Requirements:
       *
       * - The contract must not be paused.
       */
      modifier whenNotPaused() {
        _requireNotPaused();
        _;
      }
      /**
       * @dev Modifier to make a function callable only when the contract is paused.
       *
       * Requirements:
       *
       * - The contract must be paused.
       */
      modifier whenPaused() {
        _requirePaused();
        _;
      }
      /**
       * @dev Returns true if the contract is paused, and false otherwise.
       */
      function paused() public view virtual returns (bool) {
        return _paused;
      }
      /**
       * @dev Throws if the contract is paused.
       */
      function _requireNotPaused() internal view virtual {
        require(!paused(), "Pausable: paused");
      }
      /**
       * @dev Throws if the contract is not paused.
       */
      function _requirePaused() internal view virtual {
        require(paused(), "Pausable: not paused");
      }
      /**
       * @dev Triggers stopped state.
       *
       * Requirements:
       *
       * - The contract must not be paused.
       */
      function _pause() internal virtual whenNotPaused {
        _paused = true;
        emit Paused(_msgSender());
      }
      /**
       * @dev Returns to normal state.
       *
       * Requirements:
       *
       * - The contract must be paused.
       */
      function _unpause() internal virtual whenPaused {
        _paused = false;
        emit Unpaused(_msgSender());
      }
      /**
       * @dev This empty reserved space is put in place to allow future versions to add new
       * variables without shifting down storage in the inheritance chain.
       * See https://docs.openzeppelin.com/contracts/4.x/upgradeable#storage_gaps
       */
      uint256[49] private __gap;
    }
    // SPDX-License-Identifier: MIT
    // OpenZeppelin Contracts v4.4.1 (access/IAccessControlEnumerable.sol)
    pragma solidity ^0.8.0;
    import "./IAccessControlUpgradeable.sol";
    /**
     * @dev External interface of AccessControlEnumerable declared to support ERC165 detection.
     */
    interface IAccessControlEnumerableUpgradeable is IAccessControlUpgradeable {
      /**
       * @dev Returns one of the accounts that have `role`. `index` must be a
       * value between 0 and {getRoleMemberCount}, non-inclusive.
       *
       * Role bearers are not sorted in any particular way, and their ordering may
       * change at any point.
       *
       * WARNING: When using {getRoleMember} and {getRoleMemberCount}, make sure
       * you perform all queries on the same block. See the following
       * https://forum.openzeppelin.com/t/iterating-over-elements-on-enumerableset-in-openzeppelin-contracts/2296[forum post]
       * for more information.
       */
      function getRoleMember(bytes32 role, uint256 index)
        external
        view
        returns (address);
      /**
       * @dev Returns the number of accounts that have `role`. Can be used
       * together with {getRoleMember} to enumerate all bearers of a role.
       */
      function getRoleMemberCount(bytes32 role) external view returns (uint256);
    }
    // SPDX-License-Identifier: MIT
    // OpenZeppelin Contracts (last updated v4.7.0) (access/AccessControl.sol)
    pragma solidity ^0.8.0;
    import "contracts/external/openzeppelin/contracts-upgradeable/access/IAccessControlUpgradeable.sol";
    import "contracts/external/openzeppelin/contracts-upgradeable/utils/ContextUpgradeable.sol";
    import "contracts/external/openzeppelin/contracts-upgradeable/utils/StringsUpgradeable.sol";
    import "contracts/external/openzeppelin/contracts-upgradeable/utils/ERC165Upgradeable.sol";
    import "contracts/external/openzeppelin/contracts-upgradeable/proxy/Initializable.sol";
    /**
     * @dev Contract module that allows children to implement role-based access
     * control mechanisms. This is a lightweight version that doesn't allow enumerating role
     * members except through off-chain means by accessing the contract event logs. Some
     * applications may benefit from on-chain enumerability, for those cases see
     * {AccessControlEnumerable}.
     *
     * Roles are referred to by their `bytes32` identifier. These should be exposed
     * in the external API and be unique. The best way to achieve this is by
     * using `public constant` hash digests:
     *
     * ```
     * bytes32 public constant MY_ROLE = keccak256("MY_ROLE");
     * ```
     *
     * Roles can be used to represent a set of permissions. To restrict access to a
     * function call, use {hasRole}:
     *
     * ```
     * function foo() public {
     *     require(hasRole(MY_ROLE, msg.sender));
     *     ...
     * }
     * ```
     *
     * Roles can be granted and revoked dynamically via the {grantRole} and
     * {revokeRole} functions. Each role has an associated admin role, and only
     * accounts that have a role's admin role can call {grantRole} and {revokeRole}.
     *
     * By default, the admin role for all roles is `DEFAULT_ADMIN_ROLE`, which means
     * that only accounts with this role will be able to grant or revoke other
     * roles. More complex role relationships can be created by using
     * {_setRoleAdmin}.
     *
     * WARNING: The `DEFAULT_ADMIN_ROLE` is also its own admin: it has permission to
     * grant and revoke this role. Extra precautions should be taken to secure
     * accounts that have been granted it.
     */
    abstract contract AccessControlUpgradeable is
      Initializable,
      ContextUpgradeable,
      IAccessControlUpgradeable,
      ERC165Upgradeable
    {
      function __AccessControl_init() internal onlyInitializing {}
      function __AccessControl_init_unchained() internal onlyInitializing {}
      struct RoleData {
        mapping(address => bool) members;
        bytes32 adminRole;
      }
      mapping(bytes32 => RoleData) private _roles;
      bytes32 public constant DEFAULT_ADMIN_ROLE = 0x00;
      /**
       * @dev Modifier that checks that an account has a specific role. Reverts
       * with a standardized message including the required role.
       *
       * The format of the revert reason is given by the following regular expression:
       *
       *  /^AccessControl: account (0x[0-9a-f]{40}) is missing role (0x[0-9a-f]{64})$/
       *
       * _Available since v4.1._
       */
      modifier onlyRole(bytes32 role) {
        _checkRole(role);
        _;
      }
      /**
       * @dev See {IERC165-supportsInterface}.
       */
      function supportsInterface(bytes4 interfaceId)
        public
        view
        virtual
        override
        returns (bool)
      {
        return
          interfaceId == type(IAccessControlUpgradeable).interfaceId ||
          super.supportsInterface(interfaceId);
      }
      /**
       * @dev Returns `true` if `account` has been granted `role`.
       */
      function hasRole(bytes32 role, address account)
        public
        view
        virtual
        override
        returns (bool)
      {
        return _roles[role].members[account];
      }
      /**
       * @dev Revert with a standard message if `_msgSender()` is missing `role`.
       * Overriding this function changes the behavior of the {onlyRole} modifier.
       *
       * Format of the revert message is described in {_checkRole}.
       *
       * _Available since v4.6._
       */
      function _checkRole(bytes32 role) internal view virtual {
        _checkRole(role, _msgSender());
      }
      /**
       * @dev Revert with a standard message if `account` is missing `role`.
       *
       * The format of the revert reason is given by the following regular expression:
       *
       *  /^AccessControl: account (0x[0-9a-f]{40}) is missing role (0x[0-9a-f]{64})$/
       */
      function _checkRole(bytes32 role, address account) internal view virtual {
        if (!hasRole(role, account)) {
          revert(
            string(
              abi.encodePacked(
                "AccessControl: account ",
                StringsUpgradeable.toHexString(uint160(account), 20),
                " is missing role ",
                StringsUpgradeable.toHexString(uint256(role), 32)
              )
            )
          );
        }
      }
      /**
       * @dev Returns the admin role that controls `role`. See {grantRole} and
       * {revokeRole}.
       *
       * To change a role's admin, use {_setRoleAdmin}.
       */
      function getRoleAdmin(bytes32 role)
        public
        view
        virtual
        override
        returns (bytes32)
      {
        return _roles[role].adminRole;
      }
      /**
       * @dev Grants `role` to `account`.
       *
       * If `account` had not been already granted `role`, emits a {RoleGranted}
       * event.
       *
       * Requirements:
       *
       * - the caller must have ``role``'s admin role.
       *
       * May emit a {RoleGranted} event.
       */
      function grantRole(bytes32 role, address account)
        public
        virtual
        override
        onlyRole(getRoleAdmin(role))
      {
        _grantRole(role, account);
      }
      /**
       * @dev Revokes `role` from `account`.
       *
       * If `account` had been granted `role`, emits a {RoleRevoked} event.
       *
       * Requirements:
       *
       * - the caller must have ``role``'s admin role.
       *
       * May emit a {RoleRevoked} event.
       */
      function revokeRole(bytes32 role, address account)
        public
        virtual
        override
        onlyRole(getRoleAdmin(role))
      {
        _revokeRole(role, account);
      }
      /**
       * @dev Revokes `role` from the calling account.
       *
       * Roles are often managed via {grantRole} and {revokeRole}: this function's
       * purpose is to provide a mechanism for accounts to lose their privileges
       * if they are compromised (such as when a trusted device is misplaced).
       *
       * If the calling account had been revoked `role`, emits a {RoleRevoked}
       * event.
       *
       * Requirements:
       *
       * - the caller must be `account`.
       *
       * May emit a {RoleRevoked} event.
       */
      function renounceRole(bytes32 role, address account) public virtual override {
        require(
          account == _msgSender(),
          "AccessControl: can only renounce roles for self"
        );
        _revokeRole(role, account);
      }
      /**
       * @dev Grants `role` to `account`.
       *
       * If `account` had not been already granted `role`, emits a {RoleGranted}
       * event. Note that unlike {grantRole}, this function doesn't perform any
       * checks on the calling account.
       *
       * May emit a {RoleGranted} event.
       *
       * [WARNING]
       * ====
       * This function should only be called from the constructor when setting
       * up the initial roles for the system.
       *
       * Using this function in any other way is effectively circumventing the admin
       * system imposed by {AccessControl}.
       * ====
       *
       * NOTE: This function is deprecated in favor of {_grantRole}.
       */
      function _setupRole(bytes32 role, address account) internal virtual {
        _grantRole(role, account);
      }
      /**
       * @dev Sets `adminRole` as ``role``'s admin role.
       *
       * Emits a {RoleAdminChanged} event.
       */
      function _setRoleAdmin(bytes32 role, bytes32 adminRole) internal virtual {
        bytes32 previousAdminRole = getRoleAdmin(role);
        _roles[role].adminRole = adminRole;
        emit RoleAdminChanged(role, previousAdminRole, adminRole);
      }
      /**
       * @dev Grants `role` to `account`.
       *
       * Internal function without access restriction.
       *
       * May emit a {RoleGranted} event.
       */
      function _grantRole(bytes32 role, address account) internal virtual {
        if (!hasRole(role, account)) {
          _roles[role].members[account] = true;
          emit RoleGranted(role, account, _msgSender());
        }
      }
      /**
       * @dev Revokes `role` from `account`.
       *
       * Internal function without access restriction.
       *
       * May emit a {RoleRevoked} event.
       */
      function _revokeRole(bytes32 role, address account) internal virtual {
        if (hasRole(role, account)) {
          _roles[role].members[account] = false;
          emit RoleRevoked(role, account, _msgSender());
        }
      }
      /**
       * @dev This empty reserved space is put in place to allow future versions to add new
       * variables without shifting down storage in the inheritance chain.
       * See https://docs.openzeppelin.com/contracts/4.x/upgradeable#storage_gaps
       */
      uint256[49] private __gap;
    }
    // SPDX-License-Identifier: MIT
    // OpenZeppelin Contracts (last updated v4.7.0) (utils/structs/EnumerableSet.sol)
    pragma solidity ^0.8.0;
    /**
     * @dev Library for managing
     * https://en.wikipedia.org/wiki/Set_(abstract_data_type)[sets] of primitive
     * types.
     *
     * Sets have the following properties:
     *
     * - Elements are added, removed, and checked for existence in constant time
     * (O(1)).
     * - Elements are enumerated in O(n). No guarantees are made on the ordering.
     *
     * ```
     * contract Example {
     *     // Add the library methods
     *     using EnumerableSet for EnumerableSet.AddressSet;
     *
     *     // Declare a set state variable
     *     EnumerableSet.AddressSet private mySet;
     * }
     * ```
     *
     * As of v3.3.0, sets of type `bytes32` (`Bytes32Set`), `address` (`AddressSet`)
     * and `uint256` (`UintSet`) are supported.
     *
     * [WARNING]
     * ====
     *  Trying to delete such a structure from storage will likely result in data corruption, rendering the structure unusable.
     *  See https://github.com/ethereum/solidity/pull/11843[ethereum/solidity#11843] for more info.
     *
     *  In order to clean an EnumerableSet, you can either remove all elements one by one or create a fresh instance using an array of EnumerableSet.
     * ====
     */
    library EnumerableSetUpgradeable {
      // To implement this library for multiple types with as little code
      // repetition as possible, we write it in terms of a generic Set type with
      // bytes32 values.
      // The Set implementation uses private functions, and user-facing
      // implementations (such as AddressSet) are just wrappers around the
      // underlying Set.
      // This means that we can only create new EnumerableSets for types that fit
      // in bytes32.
      struct Set {
        // Storage of set values
        bytes32[] _values;
        // Position of the value in the `values` array, plus 1 because index 0
        // means a value is not in the set.
        mapping(bytes32 => uint256) _indexes;
      }
      /**
       * @dev Add a value to a set. O(1).
       *
       * Returns true if the value was added to the set, that is if it was not
       * already present.
       */
      function _add(Set storage set, bytes32 value) private returns (bool) {
        if (!_contains(set, value)) {
          set._values.push(value);
          // The value is stored at length-1, but we add 1 to all indexes
          // and use 0 as a sentinel value
          set._indexes[value] = set._values.length;
          return true;
        } else {
          return false;
        }
      }
      /**
       * @dev Removes a value from a set. O(1).
       *
       * Returns true if the value was removed from the set, that is if it was
       * present.
       */
      function _remove(Set storage set, bytes32 value) private returns (bool) {
        // We read and store the value's index to prevent multiple reads from the same storage slot
        uint256 valueIndex = set._indexes[value];
        if (valueIndex != 0) {
          // Equivalent to contains(set, value)
          // To delete an element from the _values array in O(1), we swap the element to delete with the last one in
          // the array, and then remove the last element (sometimes called as 'swap and pop').
          // This modifies the order of the array, as noted in {at}.
          uint256 toDeleteIndex = valueIndex - 1;
          uint256 lastIndex = set._values.length - 1;
          if (lastIndex != toDeleteIndex) {
            bytes32 lastValue = set._values[lastIndex];
            // Move the last value to the index where the value to delete is
            set._values[toDeleteIndex] = lastValue;
            // Update the index for the moved value
            set._indexes[lastValue] = valueIndex; // Replace lastValue's index to valueIndex
          }
          // Delete the slot where the moved value was stored
          set._values.pop();
          // Delete the index for the deleted slot
          delete set._indexes[value];
          return true;
        } else {
          return false;
        }
      }
      /**
       * @dev Returns true if the value is in the set. O(1).
       */
      function _contains(Set storage set, bytes32 value)
        private
        view
        returns (bool)
      {
        return set._indexes[value] != 0;
      }
      /**
       * @dev Returns the number of values on the set. O(1).
       */
      function _length(Set storage set) private view returns (uint256) {
        return set._values.length;
      }
      /**
       * @dev Returns the value stored at position `index` in the set. O(1).
       *
       * Note that there are no guarantees on the ordering of values inside the
       * array, and it may change when more values are added or removed.
       *
       * Requirements:
       *
       * - `index` must be strictly less than {length}.
       */
      function _at(Set storage set, uint256 index) private view returns (bytes32) {
        return set._values[index];
      }
      /**
       * @dev Return the entire set in an array
       *
       * WARNING: This operation will copy the entire storage to memory, which can be quite expensive. This is designed
       * to mostly be used by view accessors that are queried without any gas fees. Developers should keep in mind that
       * this function has an unbounded cost, and using it as part of a state-changing function may render the function
       * uncallable if the set grows to a point where copying to memory consumes too much gas to fit in a block.
       */
      function _values(Set storage set) private view returns (bytes32[] memory) {
        return set._values;
      }
      // Bytes32Set
      struct Bytes32Set {
        Set _inner;
      }
      /**
       * @dev Add a value to a set. O(1).
       *
       * Returns true if the value was added to the set, that is if it was not
       * already present.
       */
      function add(Bytes32Set storage set, bytes32 value) internal returns (bool) {
        return _add(set._inner, value);
      }
      /**
       * @dev Removes a value from a set. O(1).
       *
       * Returns true if the value was removed from the set, that is if it was
       * present.
       */
      function remove(Bytes32Set storage set, bytes32 value)
        internal
        returns (bool)
      {
        return _remove(set._inner, value);
      }
      /**
       * @dev Returns true if the value is in the set. O(1).
       */
      function contains(Bytes32Set storage set, bytes32 value)
        internal
        view
        returns (bool)
      {
        return _contains(set._inner, value);
      }
      /**
       * @dev Returns the number of values in the set. O(1).
       */
      function length(Bytes32Set storage set) internal view returns (uint256) {
        return _length(set._inner);
      }
      /**
       * @dev Returns the value stored at position `index` in the set. O(1).
       *
       * Note that there are no guarantees on the ordering of values inside the
       * array, and it may change when more values are added or removed.
       *
       * Requirements:
       *
       * - `index` must be strictly less than {length}.
       */
      function at(Bytes32Set storage set, uint256 index)
        internal
        view
        returns (bytes32)
      {
        return _at(set._inner, index);
      }
      /**
       * @dev Return the entire set in an array
       *
       * WARNING: This operation will copy the entire storage to memory, which can be quite expensive. This is designed
       * to mostly be used by view accessors that are queried without any gas fees. Developers should keep in mind that
       * this function has an unbounded cost, and using it as part of a state-changing function may render the function
       * uncallable if the set grows to a point where copying to memory consumes too much gas to fit in a block.
       */
      function values(Bytes32Set storage set)
        internal
        view
        returns (bytes32[] memory)
      {
        return _values(set._inner);
      }
      // AddressSet
      struct AddressSet {
        Set _inner;
      }
      /**
       * @dev Add a value to a set. O(1).
       *
       * Returns true if the value was added to the set, that is if it was not
       * already present.
       */
      function add(AddressSet storage set, address value) internal returns (bool) {
        return _add(set._inner, bytes32(uint256(uint160(value))));
      }
      /**
       * @dev Removes a value from a set. O(1).
       *
       * Returns true if the value was removed from the set, that is if it was
       * present.
       */
      function remove(AddressSet storage set, address value)
        internal
        returns (bool)
      {
        return _remove(set._inner, bytes32(uint256(uint160(value))));
      }
      /**
       * @dev Returns true if the value is in the set. O(1).
       */
      function contains(AddressSet storage set, address value)
        internal
        view
        returns (bool)
      {
        return _contains(set._inner, bytes32(uint256(uint160(value))));
      }
      /**
       * @dev Returns the number of values in the set. O(1).
       */
      function length(AddressSet storage set) internal view returns (uint256) {
        return _length(set._inner);
      }
      /**
       * @dev Returns the value stored at position `index` in the set. O(1).
       *
       * Note that there are no guarantees on the ordering of values inside the
       * array, and it may change when more values are added or removed.
       *
       * Requirements:
       *
       * - `index` must be strictly less than {length}.
       */
      function at(AddressSet storage set, uint256 index)
        internal
        view
        returns (address)
      {
        return address(uint160(uint256(_at(set._inner, index))));
      }
      /**
       * @dev Return the entire set in an array
       *
       * WARNING: This operation will copy the entire storage to memory, which can be quite expensive. This is designed
       * to mostly be used by view accessors that are queried without any gas fees. Developers should keep in mind that
       * this function has an unbounded cost, and using it as part of a state-changing function may render the function
       * uncallable if the set grows to a point where copying to memory consumes too much gas to fit in a block.
       */
      function values(AddressSet storage set)
        internal
        view
        returns (address[] memory)
      {
        bytes32[] memory store = _values(set._inner);
        address[] memory result;
        /// @solidity memory-safe-assembly
        assembly {
          result := store
        }
        return result;
      }
      // UintSet
      struct UintSet {
        Set _inner;
      }
      /**
       * @dev Add a value to a set. O(1).
       *
       * Returns true if the value was added to the set, that is if it was not
       * already present.
       */
      function add(UintSet storage set, uint256 value) internal returns (bool) {
        return _add(set._inner, bytes32(value));
      }
      /**
       * @dev Removes a value from a set. O(1).
       *
       * Returns true if the value was removed from the set, that is if it was
       * present.
       */
      function remove(UintSet storage set, uint256 value) internal returns (bool) {
        return _remove(set._inner, bytes32(value));
      }
      /**
       * @dev Returns true if the value is in the set. O(1).
       */
      function contains(UintSet storage set, uint256 value)
        internal
        view
        returns (bool)
      {
        return _contains(set._inner, bytes32(value));
      }
      /**
       * @dev Returns the number of values on the set. O(1).
       */
      function length(UintSet storage set) internal view returns (uint256) {
        return _length(set._inner);
      }
      /**
       * @dev Returns the value stored at position `index` in the set. O(1).
       *
       * Note that there are no guarantees on the ordering of values inside the
       * array, and it may change when more values are added or removed.
       *
       * Requirements:
       *
       * - `index` must be strictly less than {length}.
       */
      function at(UintSet storage set, uint256 index)
        internal
        view
        returns (uint256)
      {
        return uint256(_at(set._inner, index));
      }
      /**
       * @dev Return the entire set in an array
       *
       * WARNING: This operation will copy the entire storage to memory, which can be quite expensive. This is designed
       * to mostly be used by view accessors that are queried without any gas fees. Developers should keep in mind that
       * this function has an unbounded cost, and using it as part of a state-changing function may render the function
       * uncallable if the set grows to a point where copying to memory consumes too much gas to fit in a block.
       */
      function values(UintSet storage set)
        internal
        view
        returns (uint256[] memory)
      {
        bytes32[] memory store = _values(set._inner);
        uint256[] memory result;
        /// @solidity memory-safe-assembly
        assembly {
          result := store
        }
        return result;
      }
    }
    // SPDX-License-Identifier: MIT
    // OpenZeppelin Contracts (last updated v4.7.0) (utils/Address.sol)
    pragma solidity ^0.8.1;
    /**
     * @dev Collection of functions related to the address type
     */
    library AddressUpgradeable {
      /**
       * @dev Returns true if `account` is a contract.
       *
       * [IMPORTANT]
       * ====
       * It is unsafe to assume that an address for which this function returns
       * false is an externally-owned account (EOA) and not a contract.
       *
       * Among others, `isContract` will return false for the following
       * types of addresses:
       *
       *  - an externally-owned account
       *  - a contract in construction
       *  - an address where a contract will be created
       *  - an address where a contract lived, but was destroyed
       * ====
       *
       * [IMPORTANT]
       * ====
       * You shouldn't rely on `isContract` to protect against flash loan attacks!
       *
       * Preventing calls from contracts is highly discouraged. It breaks composability, breaks support for smart wallets
       * like Gnosis Safe, and does not provide security since it can be circumvented by calling from a contract
       * constructor.
       * ====
       */
      function isContract(address account) internal view returns (bool) {
        // This method relies on extcodesize/address.code.length, which returns 0
        // for contracts in construction, since the code is only stored at the end
        // of the constructor execution.
        return account.code.length > 0;
      }
      /**
       * @dev Replacement for Solidity's `transfer`: sends `amount` wei to
       * `recipient`, forwarding all available gas and reverting on errors.
       *
       * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
       * of certain opcodes, possibly making contracts go over the 2300 gas limit
       * imposed by `transfer`, making them unable to receive funds via
       * `transfer`. {sendValue} removes this limitation.
       *
       * https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
       *
       * IMPORTANT: because control is transferred to `recipient`, care must be
       * taken to not create reentrancy vulnerabilities. Consider using
       * {ReentrancyGuard} or the
       * https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
       */
      function sendValue(address payable recipient, uint256 amount) internal {
        require(address(this).balance >= amount, "Address: insufficient balance");
        (bool success, ) = recipient.call{value: amount}("");
        require(
          success,
          "Address: unable to send value, recipient may have reverted"
        );
      }
      /**
       * @dev Performs a Solidity function call using a low level `call`. A
       * plain `call` is an unsafe replacement for a function call: use this
       * function instead.
       *
       * If `target` reverts with a revert reason, it is bubbled up by this
       * function (like regular Solidity function calls).
       *
       * Returns the raw returned data. To convert to the expected return value,
       * use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
       *
       * Requirements:
       *
       * - `target` must be a contract.
       * - calling `target` with `data` must not revert.
       *
       * _Available since v3.1._
       */
      function functionCall(address target, bytes memory data)
        internal
        returns (bytes memory)
      {
        return functionCall(target, data, "Address: low-level call failed");
      }
      /**
       * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with
       * `errorMessage` as a fallback revert reason when `target` reverts.
       *
       * _Available since v3.1._
       */
      function functionCall(
        address target,
        bytes memory data,
        string memory errorMessage
      ) internal returns (bytes memory) {
        return functionCallWithValue(target, data, 0, errorMessage);
      }
      /**
       * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
       * but also transferring `value` wei to `target`.
       *
       * Requirements:
       *
       * - the calling contract must have an ETH balance of at least `value`.
       * - the called Solidity function must be `payable`.
       *
       * _Available since v3.1._
       */
      function functionCallWithValue(
        address target,
        bytes memory data,
        uint256 value
      ) internal returns (bytes memory) {
        return
          functionCallWithValue(
            target,
            data,
            value,
            "Address: low-level call with value failed"
          );
      }
      /**
       * @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
       * with `errorMessage` as a fallback revert reason when `target` reverts.
       *
       * _Available since v3.1._
       */
      function functionCallWithValue(
        address target,
        bytes memory data,
        uint256 value,
        string memory errorMessage
      ) internal returns (bytes memory) {
        require(
          address(this).balance >= value,
          "Address: insufficient balance for call"
        );
        require(isContract(target), "Address: call to non-contract");
        (bool success, bytes memory returndata) = target.call{value: value}(data);
        return verifyCallResult(success, returndata, errorMessage);
      }
      /**
       * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
       * but performing a static call.
       *
       * _Available since v3.3._
       */
      function functionStaticCall(address target, bytes memory data)
        internal
        view
        returns (bytes memory)
      {
        return
          functionStaticCall(target, data, "Address: low-level static call failed");
      }
      /**
       * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
       * but performing a static call.
       *
       * _Available since v3.3._
       */
      function functionStaticCall(
        address target,
        bytes memory data,
        string memory errorMessage
      ) internal view returns (bytes memory) {
        require(isContract(target), "Address: static call to non-contract");
        (bool success, bytes memory returndata) = target.staticcall(data);
        return verifyCallResult(success, returndata, errorMessage);
      }
      /**
       * @dev Tool to verifies that a low level call was successful, and revert if it wasn't, either by bubbling the
       * revert reason using the provided one.
       *
       * _Available since v4.3._
       */
      function verifyCallResult(
        bool success,
        bytes memory returndata,
        string memory errorMessage
      ) internal pure returns (bytes memory) {
        if (success) {
          return returndata;
        } else {
          // Look for revert reason and bubble it up if present
          if (returndata.length > 0) {
            // The easiest way to bubble the revert reason is using memory via assembly
            /// @solidity memory-safe-assembly
            assembly {
              let returndata_size := mload(returndata)
              revert(add(32, returndata), returndata_size)
            }
          } else {
            revert(errorMessage);
          }
        }
      }
    }
    // SPDX-License-Identifier: MIT
    // OpenZeppelin Contracts v4.4.1 (access/IAccessControl.sol)
    pragma solidity ^0.8.0;
    /**
     * @dev External interface of AccessControl declared to support ERC165 detection.
     */
    interface IAccessControlUpgradeable {
      /**
       * @dev Emitted when `newAdminRole` is set as ``role``'s admin role, replacing `previousAdminRole`
       *
       * `DEFAULT_ADMIN_ROLE` is the starting admin for all roles, despite
       * {RoleAdminChanged} not being emitted signaling this.
       *
       * _Available since v3.1._
       */
      event RoleAdminChanged(
        bytes32 indexed role,
        bytes32 indexed previousAdminRole,
        bytes32 indexed newAdminRole
      );
      /**
       * @dev Emitted when `account` is granted `role`.
       *
       * `sender` is the account that originated the contract call, an admin role
       * bearer except when using {AccessControl-_setupRole}.
       */
      event RoleGranted(
        bytes32 indexed role,
        address indexed account,
        address indexed sender
      );
      /**
       * @dev Emitted when `account` is revoked `role`.
       *
       * `sender` is the account that originated the contract call:
       *   - if using `revokeRole`, it is the admin role bearer
       *   - if using `renounceRole`, it is the role bearer (i.e. `account`)
       */
      event RoleRevoked(
        bytes32 indexed role,
        address indexed account,
        address indexed sender
      );
      /**
       * @dev Returns `true` if `account` has been granted `role`.
       */
      function hasRole(bytes32 role, address account) external view returns (bool);
      /**
       * @dev Returns the admin role that controls `role`. See {grantRole} and
       * {revokeRole}.
       *
       * To change a role's admin, use {AccessControl-_setRoleAdmin}.
       */
      function getRoleAdmin(bytes32 role) external view returns (bytes32);
      /**
       * @dev Grants `role` to `account`.
       *
       * If `account` had not been already granted `role`, emits a {RoleGranted}
       * event.
       *
       * Requirements:
       *
       * - the caller must have ``role``'s admin role.
       */
      function grantRole(bytes32 role, address account) external;
      /**
       * @dev Revokes `role` from `account`.
       *
       * If `account` had been granted `role`, emits a {RoleRevoked} event.
       *
       * Requirements:
       *
       * - the caller must have ``role``'s admin role.
       */
      function revokeRole(bytes32 role, address account) external;
      /**
       * @dev Revokes `role` from the calling account.
       *
       * Roles are often managed via {grantRole} and {revokeRole}: this function's
       * purpose is to provide a mechanism for accounts to lose their privileges
       * if they are compromised (such as when a trusted device is misplaced).
       *
       * If the calling account had been granted `role`, emits a {RoleRevoked}
       * event.
       *
       * Requirements:
       *
       * - the caller must be `account`.
       */
      function renounceRole(bytes32 role, address account) external;
    }
    // SPDX-License-Identifier: MIT
    // OpenZeppelin Contracts (last updated v4.7.0) (utils/Strings.sol)
    pragma solidity ^0.8.0;
    /**
     * @dev String operations.
     */
    library StringsUpgradeable {
      bytes16 private constant _HEX_SYMBOLS = "0123456789abcdef";
      uint8 private constant _ADDRESS_LENGTH = 20;
      /**
       * @dev Converts a `uint256` to its ASCII `string` decimal representation.
       */
      function toString(uint256 value) internal pure returns (string memory) {
        // Inspired by OraclizeAPI's implementation - MIT licence
        // https://github.com/oraclize/ethereum-api/blob/b42146b063c7d6ee1358846c198246239e9360e8/oraclizeAPI_0.4.25.sol
        if (value == 0) {
          return "0";
        }
        uint256 temp = value;
        uint256 digits;
        while (temp != 0) {
          digits++;
          temp /= 10;
        }
        bytes memory buffer = new bytes(digits);
        while (value != 0) {
          digits -= 1;
          buffer[digits] = bytes1(uint8(48 + uint256(value % 10)));
          value /= 10;
        }
        return string(buffer);
      }
      /**
       * @dev Converts a `uint256` to its ASCII `string` hexadecimal representation.
       */
      function toHexString(uint256 value) internal pure returns (string memory) {
        if (value == 0) {
          return "0x00";
        }
        uint256 temp = value;
        uint256 length = 0;
        while (temp != 0) {
          length++;
          temp >>= 8;
        }
        return toHexString(value, length);
      }
      /**
       * @dev Converts a `uint256` to its ASCII `string` hexadecimal representation with fixed length.
       */
      function toHexString(uint256 value, uint256 length)
        internal
        pure
        returns (string memory)
      {
        bytes memory buffer = new bytes(2 * length + 2);
        buffer[0] = "0";
        buffer[1] = "x";
        for (uint256 i = 2 * length + 1; i > 1; --i) {
          buffer[i] = _HEX_SYMBOLS[value & 0xf];
          value >>= 4;
        }
        require(value == 0, "Strings: hex length insufficient");
        return string(buffer);
      }
      /**
       * @dev Converts an `address` with fixed length of 20 bytes to its not checksummed ASCII `string` hexadecimal representation.
       */
      function toHexString(address addr) internal pure returns (string memory) {
        return toHexString(uint256(uint160(addr)), _ADDRESS_LENGTH);
      }
    }
    // SPDX-License-Identifier: MIT
    // OpenZeppelin Contracts v4.4.1 (utils/introspection/ERC165.sol)
    pragma solidity ^0.8.0;
    import "contracts/external/openzeppelin/contracts-upgradeable/utils/IERC165Upgradeable.sol";
    import "contracts/external/openzeppelin/contracts-upgradeable/proxy/Initializable.sol";
    /**
     * @dev Implementation of the {IERC165} interface.
     *
     * Contracts that want to implement ERC165 should inherit from this contract and override {supportsInterface} to check
     * for the additional interface id that will be supported. For example:
     *
     * ```solidity
     * function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) {
     *     return interfaceId == type(MyInterface).interfaceId || super.supportsInterface(interfaceId);
     * }
     * ```
     *
     * Alternatively, {ERC165Storage} provides an easier to use but more expensive implementation.
     */
    abstract contract ERC165Upgradeable is Initializable, IERC165Upgradeable {
      function __ERC165_init() internal onlyInitializing {}
      function __ERC165_init_unchained() internal onlyInitializing {}
      /**
       * @dev See {IERC165-supportsInterface}.
       */
      function supportsInterface(bytes4 interfaceId)
        public
        view
        virtual
        override
        returns (bool)
      {
        return interfaceId == type(IERC165Upgradeable).interfaceId;
      }
      /**
       * @dev This empty reserved space is put in place to allow future versions to add new
       * variables without shifting down storage in the inheritance chain.
       * See https://docs.openzeppelin.com/contracts/4.x/upgradeable#storage_gaps
       */
      uint256[50] private __gap;
    }
    // SPDX-License-Identifier: MIT
    // OpenZeppelin Contracts v4.4.1 (utils/introspection/IERC165.sol)
    pragma solidity ^0.8.0;
    /**
     * @dev Interface of the ERC165 standard, as defined in the
     * https://eips.ethereum.org/EIPS/eip-165[EIP].
     *
     * Implementers can declare support of contract interfaces, which can then be
     * queried by others ({ERC165Checker}).
     *
     * For an implementation, see {ERC165}.
     */
    interface IERC165Upgradeable {
      /**
       * @dev Returns true if this contract implements the interface defined by
       * `interfaceId`. See the corresponding
       * https://eips.ethereum.org/EIPS/eip-165#how-interfaces-are-identified[EIP section]
       * to learn more about how these ids are created.
       *
       * This function call must use less than 30 000 gas.
       */
      function supportsInterface(bytes4 interfaceId) external view returns (bool);
    }