creation_sourcecode: // SPDX-License-Identifier: MIT
  // File: @openzeppelin/contracts-upgradeable/token/ERC20/IERC20Upgradeable.sol
  
  // OpenZeppelin Contracts v4.4.1 (token/ERC20/IERC20.sol)
  
  pragma solidity ^0.8.0;
  
  /**
   * @dev Interface of the ERC20 standard as defined in the EIP.
   */
  interface IERC20Upgradeable {
      /**
       * @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 `recipient`.
       *
       * Returns a boolean value indicating whether the operation succeeded.
       *
       * Emits a {Transfer} event.
       */
      function transfer(address recipient, 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 `sender` to `recipient` 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 sender,
          address recipient,
          uint256 amount
      ) external returns (bool);
  
      /**
       * @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);
  }
  
  // File: @openzeppelin/contracts-upgradeable/token/ERC20/extensions/IERC20MetadataUpgradeable.sol
  
  // OpenZeppelin Contracts v4.4.1 (token/ERC20/extensions/IERC20Metadata.sol)
  
  pragma solidity ^0.8.0;
  
  /**
   * @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);
  }
  
  // File: @openzeppelin/contracts-upgradeable/utils/AddressUpgradeable.sol
  
  // OpenZeppelin Contracts v4.4.1 (utils/Address.sol)
  
  pragma solidity ^0.8.0;
  
  /**
   * @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
       * ====
       */
      function isContract(address account) internal view returns (bool) {
          // This method relies on extcodesize, which returns 0 for contracts in
          // construction, since the code is only stored at the end of the
          // constructor execution.
  
          uint256 size;
          assembly {
              size := extcodesize(account)
          }
          return size > 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
  
                  assembly {
                      let returndata_size := mload(returndata)
                      revert(add(32, returndata), returndata_size)
                  }
              } else {
                  revert(errorMessage);
              }
          }
      }
  }
  
  // File: @openzeppelin/contracts-upgradeable/proxy/utils/Initializable.sol
  
  // OpenZeppelin Contracts v4.4.1 (proxy/utils/Initializable.sol)
  
  pragma solidity ^0.8.0;
  
  /**
   * @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 a proxied contract can't have 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.
   *
   * 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 initialize the implementation contract, you can either invoke the
   * initializer manually, or you can include a constructor to automatically mark it as initialized when it is deployed:
   *
   * [.hljs-theme-light.nopadding]
   * ```
   * /// @custom:oz-upgrades-unsafe-allow constructor
   * constructor() initializer {}
   * ```
   * ====
   */
  abstract contract Initializable {
      /**
       * @dev Indicates that the contract has been initialized.
       */
      bool private _initialized;
  
      /**
       * @dev Indicates that the contract is in the process of being initialized.
       */
      bool private _initializing;
  
      /**
       * @dev Modifier to protect an initializer function from being invoked twice.
       */
      modifier initializer() {
          // If the contract is initializing we ignore whether _initialized is set in order to support multiple
          // inheritance patterns, but we only do this in the context of a constructor, because in other contexts the
          // contract may have been reentered.
          require(_initializing ? _isConstructor() : !_initialized, "Initializable: contract is already initialized");
  
          bool isTopLevelCall = !_initializing;
          if (isTopLevelCall) {
              _initializing = true;
              _initialized = true;
          }
  
          _;
  
          if (isTopLevelCall) {
              _initializing = false;
          }
      }
  
      /**
       * @dev Modifier to protect an initialization function so that it can only be invoked by functions with the
       * {initializer} modifier, directly or indirectly.
       */
      modifier onlyInitializing() {
          require(_initializing, "Initializable: contract is not initializing");
          _;
      }
  
      function _isConstructor() private view returns (bool) {
          return !AddressUpgradeable.isContract(address(this));
      }
  }
  
  // File: @openzeppelin/contracts-upgradeable/utils/ContextUpgradeable.sol
  
  // OpenZeppelin Contracts v4.4.1 (utils/Context.sol)
  
  pragma solidity ^0.8.0;
  
  /**
   * @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 {
          __Context_init_unchained();
      }
  
      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;
      }
      uint256[50] private __gap;
  }
  
  // File: @openzeppelin/contracts-upgradeable/token/ERC20/ERC20Upgradeable.sol
  
  // OpenZeppelin Contracts v4.4.1 (token/ERC20/ERC20.sol)
  
  pragma solidity ^0.8.0;
  
  
  
  
  /**
   * @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 {
          __Context_init_unchained();
          __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:
       *
       * - `recipient` cannot be the zero address.
       * - the caller must have a balance of at least `amount`.
       */
      function transfer(address recipient, uint256 amount) public virtual override returns (bool) {
          _transfer(_msgSender(), recipient, 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}.
       *
       * Requirements:
       *
       * - `spender` cannot be the zero address.
       */
      function approve(address spender, uint256 amount) public virtual override returns (bool) {
          _approve(_msgSender(), 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}.
       *
       * Requirements:
       *
       * - `sender` and `recipient` cannot be the zero address.
       * - `sender` must have a balance of at least `amount`.
       * - the caller must have allowance for ``sender``'s tokens of at least
       * `amount`.
       */
      function transferFrom(
          address sender,
          address recipient,
          uint256 amount
      ) public virtual override returns (bool) {
          _transfer(sender, recipient, amount);
  
          uint256 currentAllowance = _allowances[sender][_msgSender()];
          require(currentAllowance >= amount, "ERC20: transfer amount exceeds allowance");
          unchecked {
              _approve(sender, _msgSender(), currentAllowance - 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) {
          _approve(_msgSender(), spender, _allowances[_msgSender()][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) {
          uint256 currentAllowance = _allowances[_msgSender()][spender];
          require(currentAllowance >= subtractedValue, "ERC20: decreased allowance below zero");
          unchecked {
              _approve(_msgSender(), spender, currentAllowance - subtractedValue);
          }
  
          return true;
      }
  
      /**
       * @dev Moves `amount` of tokens from `sender` to `recipient`.
       *
       * 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:
       *
       * - `sender` cannot be the zero address.
       * - `recipient` cannot be the zero address.
       * - `sender` must have a balance of at least `amount`.
       */
      function _transfer(
          address sender,
          address recipient,
          uint256 amount
      ) internal virtual {
          require(sender != address(0), "ERC20: transfer from the zero address");
          require(recipient != address(0), "ERC20: transfer to the zero address");
  
          _beforeTokenTransfer(sender, recipient, amount);
  
          uint256 senderBalance = _balances[sender];
          require(senderBalance >= amount, "ERC20: transfer amount exceeds balance");
          unchecked {
              _balances[sender] = senderBalance - amount;
          }
          _balances[recipient] += amount;
  
          emit Transfer(sender, recipient, amount);
  
          _afterTokenTransfer(sender, recipient, 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 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 {}
      uint256[45] private __gap;
  }
  
  // File: @openzeppelin/contracts-upgradeable/token/ERC20/utils/SafeERC20Upgradeable.sol
  
  // OpenZeppelin Contracts v4.4.1 (token/ERC20/utils/SafeERC20.sol)
  
  pragma solidity ^0.8.0;
  
  
  /**
   * @title SafeERC20
   * @dev Wrappers around ERC20 operations that throw on failure (when the token
   * contract returns false). Tokens that return no value (and instead revert or
   * throw on failure) are also supported, non-reverting calls are assumed to be
   * successful.
   * To use this library you can add a `using SafeERC20 for IERC20;` statement to your contract,
   * which allows you to call the safe operations as `token.safeTransfer(...)`, etc.
   */
  library SafeERC20Upgradeable {
      using AddressUpgradeable for address;
  
      function safeTransfer(
          IERC20Upgradeable token,
          address to,
          uint256 value
      ) internal {
          _callOptionalReturn(token, abi.encodeWithSelector(token.transfer.selector, to, value));
      }
  
      function safeTransferFrom(
          IERC20Upgradeable token,
          address from,
          address to,
          uint256 value
      ) internal {
          _callOptionalReturn(token, abi.encodeWithSelector(token.transferFrom.selector, from, to, value));
      }
  
      /**
       * @dev Deprecated. This function has issues similar to the ones found in
       * {IERC20-approve}, and its usage is discouraged.
       *
       * Whenever possible, use {safeIncreaseAllowance} and
       * {safeDecreaseAllowance} instead.
       */
      function safeApprove(
          IERC20Upgradeable token,
          address spender,
          uint256 value
      ) internal {
          // safeApprove should only be called when setting an initial allowance,
          // or when resetting it to zero. To increase and decrease it, use
          // 'safeIncreaseAllowance' and 'safeDecreaseAllowance'
          require(
              (value == 0) || (token.allowance(address(this), spender) == 0),
              "SafeERC20: approve from non-zero to non-zero allowance"
          );
          _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, value));
      }
  
      function safeIncreaseAllowance(
          IERC20Upgradeable token,
          address spender,
          uint256 value
      ) internal {
          uint256 newAllowance = token.allowance(address(this), spender) + value;
          _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
      }
  
      function safeDecreaseAllowance(
          IERC20Upgradeable token,
          address spender,
          uint256 value
      ) internal {
          unchecked {
              uint256 oldAllowance = token.allowance(address(this), spender);
              require(oldAllowance >= value, "SafeERC20: decreased allowance below zero");
              uint256 newAllowance = oldAllowance - value;
              _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
          }
      }
  
      /**
       * @dev Imitates a Solidity high-level call (i.e. a regular function call to a contract), relaxing the requirement
       * on the return value: the return value is optional (but if data is returned, it must not be false).
       * @param token The token targeted by the call.
       * @param data The call data (encoded using abi.encode or one of its variants).
       */
      function _callOptionalReturn(IERC20Upgradeable token, bytes memory data) private {
          // We need to perform a low level call here, to bypass Solidity's return data size checking mechanism, since
          // we're implementing it ourselves. We use {Address.functionCall} to perform this call, which verifies that
          // the target address contains contract code and also asserts for success in the low-level call.
  
          bytes memory returndata = address(token).functionCall(data, "SafeERC20: low-level call failed");
          if (returndata.length > 0) {
              // Return data is optional
              require(abi.decode(returndata, (bool)), "SafeERC20: ERC20 operation did not succeed");
          }
      }
  }
  
  // File: @openzeppelin/contracts-upgradeable/access/OwnableUpgradeable.sol
  
  // OpenZeppelin Contracts v4.4.1 (access/Ownable.sol)
  
  pragma solidity ^0.8.0;
  
  
  /**
   * @dev Contract module which provides a basic access control mechanism, where
   * there is an account (an owner) that can be granted exclusive access to
   * specific functions.
   *
   * By default, the owner account will be the one that deploys the contract. This
   * can later be changed with {transferOwnership}.
   *
   * This module is used through inheritance. It will make available the modifier
   * `onlyOwner`, which can be applied to your functions to restrict their use to
   * the owner.
   */
  abstract contract OwnableUpgradeable is Initializable, ContextUpgradeable {
      address private _owner;
  
      event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);
  
      /**
       * @dev Initializes the contract setting the deployer as the initial owner.
       */
      function __Ownable_init() internal onlyInitializing {
          __Context_init_unchained();
          __Ownable_init_unchained();
      }
  
      function __Ownable_init_unchained() internal onlyInitializing {
          _transferOwnership(_msgSender());
      }
  
      /**
       * @dev Returns the address of the current owner.
       */
      function owner() public view virtual returns (address) {
          return _owner;
      }
  
      /**
       * @dev Throws if called by any account other than the owner.
       */
      modifier onlyOwner() {
          require(owner() == _msgSender(), "Ownable: caller is not the owner");
          _;
      }
  
      /**
       * @dev Leaves the contract without owner. It will not be possible to call
       * `onlyOwner` functions anymore. Can only be called by the current owner.
       *
       * NOTE: Renouncing ownership will leave the contract without an owner,
       * thereby removing any functionality that is only available to the owner.
       */
      function renounceOwnership() public virtual onlyOwner {
          _transferOwnership(address(0));
      }
  
      /**
       * @dev Transfers ownership of the contract to a new account (`newOwner`).
       * Can only be called by the current owner.
       */
      function transferOwnership(address newOwner) public virtual onlyOwner {
          require(newOwner != address(0), "Ownable: new owner is the zero address");
          _transferOwnership(newOwner);
      }
  
      /**
       * @dev Transfers ownership of the contract to a new account (`newOwner`).
       * Internal function without access restriction.
       */
      function _transferOwnership(address newOwner) internal virtual {
          address oldOwner = _owner;
          _owner = newOwner;
          emit OwnershipTransferred(oldOwner, newOwner);
      }
      uint256[49] private __gap;
  }
  
  // File: @openzeppelin/contracts-upgradeable/security/ReentrancyGuardUpgradeable.sol
  
  // OpenZeppelin Contracts v4.4.1 (security/ReentrancyGuard.sol)
  
  pragma solidity ^0.8.0;
  
  /**
   * @dev Contract module that helps prevent reentrant calls to a function.
   *
   * Inheriting from `ReentrancyGuard` will make the {nonReentrant} modifier
   * available, which can be applied to functions to make sure there are no nested
   * (reentrant) calls to them.
   *
   * Note that because there is a single `nonReentrant` guard, functions marked as
   * `nonReentrant` may not call one another. This can be worked around by making
   * those functions `private`, and then adding `external` `nonReentrant` entry
   * points to them.
   *
   * TIP: If you would like to learn more about reentrancy and alternative ways
   * to protect against it, check out our blog post
   * https://blog.openzeppelin.com/reentrancy-after-istanbul/[Reentrancy After Istanbul].
   */
  abstract contract ReentrancyGuardUpgradeable is Initializable {
      // Booleans are more expensive than uint256 or any type that takes up a full
      // word because each write operation emits an extra SLOAD to first read the
      // slot's contents, replace the bits taken up by the boolean, and then write
      // back. This is the compiler's defense against contract upgrades and
      // pointer aliasing, and it cannot be disabled.
  
      // The values being non-zero value makes deployment a bit more expensive,
      // but in exchange the refund on every call to nonReentrant will be lower in
      // amount. Since refunds are capped to a percentage of the total
      // transaction's gas, it is best to keep them low in cases like this one, to
      // increase the likelihood of the full refund coming into effect.
      uint256 private constant _NOT_ENTERED = 1;
      uint256 private constant _ENTERED = 2;
  
      uint256 private _status;
  
      function __ReentrancyGuard_init() internal onlyInitializing {
          __ReentrancyGuard_init_unchained();
      }
  
      function __ReentrancyGuard_init_unchained() internal onlyInitializing {
          _status = _NOT_ENTERED;
      }
  
      /**
       * @dev Prevents a contract from calling itself, directly or indirectly.
       * Calling a `nonReentrant` function from another `nonReentrant`
       * function is not supported. It is possible to prevent this from happening
       * by making the `nonReentrant` function external, and making it call a
       * `private` function that does the actual work.
       */
      modifier nonReentrant() {
          // On the first call to nonReentrant, _notEntered will be true
          require(_status != _ENTERED, "ReentrancyGuard: reentrant call");
  
          // Any calls to nonReentrant after this point will fail
          _status = _ENTERED;
  
          _;
  
          // By storing the original value once again, a refund is triggered (see
          // https://eips.ethereum.org/EIPS/eip-2200)
          _status = _NOT_ENTERED;
      }
      uint256[49] private __gap;
  }
  
  // File: contracts/BIFI/interfaces/beefy/IStrategyV7.sol
  
  
  pragma solidity ^0.8.0;
  interface IStrategyV7 {
      function vault() external view returns (address);
      function want() external view returns (IERC20Upgradeable);
      function beforeDeposit() external;
      function deposit() external;
      function withdraw(uint256) external;
      function balanceOf() external view returns (uint256);
      function balanceOfWant() external view returns (uint256);
      function balanceOfPool() external view returns (uint256);
      function harvest() external;
      function retireStrat() external;
      function panic() external;
      function pause() external;
      function unpause() external;
      function paused() external view returns (bool);
      function unirouter() external view returns (address);
  }
  
  // File: contracts/BIFI/vaults/BeefyVaultV7.sol
  
  
  pragma solidity ^0.8.0;
  /**
   * @dev Implementation of a vault to deposit funds for yield optimizing.
   * This is the contract that receives funds and that users interface with.
   * The yield optimizing strategy itself is implemented in a separate 'Strategy.sol' contract.
   */
  contract BeefyVaultV7 is ERC20Upgradeable, OwnableUpgradeable, ReentrancyGuardUpgradeable {
      using SafeERC20Upgradeable for IERC20Upgradeable;
  
      struct StratCandidate {
          address implementation;
          uint proposedTime;
      }
  
      // The last proposed strategy to switch to.
      StratCandidate public stratCandidate;
      // The strategy currently in use by the vault.
      IStrategyV7 public strategy;
      // The minimum time it has to pass before a strat candidate can be approved.
      uint256 public approvalDelay;
  
      event NewStratCandidate(address implementation);
      event UpgradeStrat(address implementation);
  
      /**
       * @dev Sets the value of {token} to the token that the vault will
       * hold as underlying value. It initializes the vault's own 'moo' token.
       * This token is minted when someone does a deposit. It is burned in order
       * to withdraw the corresponding portion of the underlying assets.
       * @param _strategy the address of the strategy.
       * @param _name the name of the vault token.
       * @param _symbol the symbol of the vault token.
       * @param _approvalDelay the delay before a new strat can be approved.
       */
       function initialize(
          IStrategyV7 _strategy,
          string memory _name,
          string memory _symbol,
          uint256 _approvalDelay
      ) public initializer {
          __ERC20_init(_name, _symbol);
          __Ownable_init();
          __ReentrancyGuard_init();
          strategy = _strategy;
          approvalDelay = _approvalDelay;
      }
  
      function want() public view returns (IERC20Upgradeable) {
          return IERC20Upgradeable(strategy.want());
      }
  
      /**
       * @dev It calculates the total underlying value of {token} held by the system.
       * It takes into account the vault contract balance, the strategy contract balance
       *  and the balance deployed in other contracts as part of the strategy.
       */
      function balance() public view returns (uint) {
          return want().balanceOf(address(this)) + IStrategyV7(strategy).balanceOf();
      }
  
      /**
       * @dev Custom logic in here for how much the vault allows to be borrowed.
       * We return 100% of tokens for now. Under certain conditions we might
       * want to keep some of the system funds at hand in the vault, instead
       * of putting them to work.
       */
      function available() public view returns (uint256) {
          return want().balanceOf(address(this));
      }
  
      /**
       * @dev Function for various UIs to display the current value of one of our yield tokens.
       * Returns an uint256 with 18 decimals of how much underlying asset one vault share represents.
       */
      function getPricePerFullShare() public view returns (uint256) {
          return totalSupply() == 0 ? 1e18 : balance() * 1e18 / totalSupply();
      }
  
      /**
       * @dev A helper function to call deposit() with all the sender's funds.
       */
      function depositAll() external {
          deposit(want().balanceOf(msg.sender));
      }
  
      /**
       * @dev The entrypoint of funds into the system. People deposit with this function
       * into the vault. The vault is then in charge of sending funds into the strategy.
       */
      function deposit(uint _amount) public nonReentrant {
          strategy.beforeDeposit();
  
          uint256 _pool = balance();
          want().safeTransferFrom(msg.sender, address(this), _amount);
          earn();
          uint256 _after = balance();
          _amount = _after - _pool; // Additional check for deflationary tokens
          uint256 shares = 0;
          if (totalSupply() == 0) {
              shares = _amount;
          } else {
              shares = (_amount * totalSupply()) / _pool;
          }
          _mint(msg.sender, shares);
      }
  
      /**
       * @dev Function to send funds into the strategy and put them to work. It's primarily called
       * by the vault's deposit() function.
       */
      function earn() public {
          uint _bal = available();
          want().safeTransfer(address(strategy), _bal);
          strategy.deposit();
      }
  
      /**
       * @dev A helper function to call withdraw() with all the sender's funds.
       */
      function withdrawAll() external {
          withdraw(balanceOf(msg.sender));
      }
  
      /**
       * @dev Function to exit the system. The vault will withdraw the required tokens
       * from the strategy and pay up the token holder. A proportional number of IOU
       * tokens are burned in the process.
       */
      function withdraw(uint256 _shares) public {
          uint256 r = (balance() * _shares) / totalSupply();
          _burn(msg.sender, _shares);
  
          uint b = want().balanceOf(address(this));
          if (b < r) {
              uint _withdraw = r - b;
              strategy.withdraw(_withdraw);
              uint _after = want().balanceOf(address(this));
              uint _diff = _after - b;
              if (_diff < _withdraw) {
                  r = b + _diff;
              }
          }
  
          want().safeTransfer(msg.sender, r);
      }
  
      /** 
       * @dev Sets the candidate for the new strat to use with this vault.
       * @param _implementation The address of the candidate strategy.  
       */
      function proposeStrat(address _implementation) public onlyOwner {
          require(address(this) == IStrategyV7(_implementation).vault(), "Proposal not valid for this Vault");
          require(want() == IStrategyV7(_implementation).want(), "Different want");
          stratCandidate = StratCandidate({
              implementation: _implementation,
              proposedTime: block.timestamp
           });
  
          emit NewStratCandidate(_implementation);
      }
  
      /** 
       * @dev It switches the active strat for the strat candidate. After upgrading, the 
       * candidate implementation is set to the 0x00 address, and proposedTime to a time 
       * happening in +100 years for safety. 
       */
  
      function upgradeStrat() public onlyOwner {
          require(stratCandidate.implementation != address(0), "There is no candidate");
          require(stratCandidate.proposedTime + approvalDelay < block.timestamp, "Delay has not passed");
  
          emit UpgradeStrat(stratCandidate.implementation);
  
          strategy.retireStrat();
          strategy = IStrategyV7(stratCandidate.implementation);
          stratCandidate.implementation = address(0);
          stratCandidate.proposedTime = 5000000000;
  
          earn();
      }
  
      /**
       * @dev Rescues random funds stuck that the strat can't handle.
       * @param _token address of the token to rescue.
       */
      function inCaseTokensGetStuck(address _token) external onlyOwner {
          require(_token != address(want()), "!token");
  
          uint256 amount = IERC20Upgradeable(_token).balanceOf(address(this));
          IERC20Upgradeable(_token).safeTransfer(msg.sender, amount);
      }
  }