def _check_signature(func, mock, skipfirst):
    if not _callable(func):
        return

    result = _getsignature2(func, skipfirst)
    if result is None:
        return
    signature, func = result

    src = signature % "lambda self, %s: None"
    checksig = eval(src, {})
    _copy_func_details(func, checksig)
    type(mock)._mock_check_sig = checksig
dataset/ETHPy150Open sibson/vncdotool/tests/unit/mock.py/_check_signature/swapped operands of `%`