// File: contracts/_external/ozproxy/transparent/TransparentUpgradeableProxy.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (proxy/transparent/TransparentUpgradeableProxy.sol)

pragma solidity 0.8.9;

import "../ERC1967/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();
  }
}

// File: contracts/_external/ozproxy/ERC1967/ERC1967Proxy.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (proxy/ERC1967/ERC1967Proxy.sol)

pragma solidity 0.8.9;

import "../Proxy.sol";
import "./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();
  }
}

// File: contracts/_external/ozproxy/Proxy.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (proxy/Proxy.sol)

pragma solidity 0.8.9;

/**
 * @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 virtual {
    _fallback();
  }

  /**
   * @dev Fallback function that delegates calls to the address returned by `_implementation()`. Will run if call data
   * is empty.
   */
  receive() external payable virtual {
    _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 {}
}

// File: contracts/_external/ozproxy/ERC1967/ERC1967Upgrade.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (proxy/ERC1967/ERC1967Upgrade.sol)

pragma solidity 0.8.9;

import "../beacon/IBeacon.sol";
import "./Address.sol";
import "./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 _upgradeToAndCallSecure(
    address newImplementation,
    bytes memory data,
    bool forceCall
  ) internal {
    address oldImplementation = _getImplementation();

    // Initial upgrade and setup call
    _setImplementation(newImplementation);
    if (data.length > 0 || forceCall) {
      Address.functionDelegateCall(newImplementation, data);
    }

    // Perform rollback test if not already in progress
    StorageSlot.BooleanSlot storage rollbackTesting = StorageSlot.getBooleanSlot(_ROLLBACK_SLOT);
    if (!rollbackTesting.value) {
      // Trigger rollback using upgradeTo from the new implementation
      rollbackTesting.value = true;
      Address.functionDelegateCall(newImplementation, abi.encodeWithSignature("upgradeTo(address)", oldImplementation));
      rollbackTesting.value = false;
      // Check rollback was effective
      require(oldImplementation == _getImplementation(), "ERC1967Upgrade: upgrade breaks further upgrades");
      // Finally reset to the new implementation and log the upgrade
      _upgradeTo(newImplementation);
    }
  }

  /**
   * @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);
    }
  }
}

// File: contracts/_external/ozproxy/beacon/IBeacon.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (proxy/beacon/IBeacon.sol)

pragma solidity 0.8.9;

/**
 * @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);
}

// File: contracts/_external/ozproxy/ERC1967/Address.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/Address.sol)

pragma solidity 0.8.9;

/**
 * @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);
      }
    }
  }
}

// File: contracts/_external/ozproxy/ERC1967/StorageSlot.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/StorageSlot.sol)

pragma solidity 0.8.9;

/**
 * @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
    }
  }
}