    function _returnETHIfAny(address recipient) internal {
        assembly {
            if gt(selfbalance(), 0) {
                let status := call(gas(), recipient, selfbalance(), 0, 0, 0, 0) // @audit-issue status not checked.
            }
        }
    }
    function _returnETHIfAny() internal {
        bool status;
        assembly {
            if gt(selfbalance(), 0) {
                status := call(gas(), caller(), selfbalance(), 0, 0, 0, 0) // @audit-issue [MED] status not checked
            }
        }
        if (!status) revert ETHTransferFail();
    }

    function _returnETHIfAny(address recipient) internal {
        bool status;
        assembly {
            if gt(selfbalance(), 0) {
                status := call(gas(), recipient, selfbalance(), 0, 0, 0, 0) // @audit-issue status not checked.
            }
        }
        if (!status) revert ETHTransferFail();
    }
function _returnETHIfAnyWithOneWeiLeft() internal {
        bool status;
        assembly {
            if gt(selfbalance(), 1) {
                status := call(gas(), caller(), sub(selfbalance(), 1), 0, 0, 0, 0)
            }
        }
        if (!status) revert ETHTransferFail();
    }
