abstract contract Proxy {
	/**
	 * @dev Receive function.
	 * Implemented entirely in `_fallback`.
	 */
	receive() external payable virtual {
		_fallback();
	}

	/**
	 * @dev Fallback function.
	 * Implemented entirely in `_fallback`.
	 */
	fallback() external payable {
		_fallback();
	}

	/**
	 * @return impl The Address of the implementation.
	 */
	function _implementation() internal virtual view returns (address impl);

	/**
	 * @dev Delegates execution to an implementation contract.
	 * This is a low level function that doesn't return to its internal call site.
	 * It will return to the external caller whatever the implementation returns.
	 * @param implementation Address to delegate.
	 */
	function _delegate(address implementation) internal {
		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 Function that is run as the first thing in the fallback function.
	 * Can be redefined in derived contracts to add functionality.
	 * Redefinitions must call super._willFallback().
	 */
	function _willFallback() internal virtual {
	}

	/**
	 * @dev fallback implementation.
	 * Extracted to enable manual triggering.
	 */
	function _fallback() internal {
		_willFallback();
		_delegate(_implementation());
	}
}
/**
 * @title Proxy
 * @dev Implements delegation of calls to other contracts, with proper
 * forwarding of return values and bubbling of failures.
 * It defines a fallback function that delegates all calls to the address
 * returned by the abstract _implementation() internal function.
 */
function _implementation() internal virtual view returns (address impl);
/**
 	 * @return impl The Address of the implementation.
 	 */