def end_optgroup(self):
        debug("")
        if self._optgroup is not None:
            raise ParseError("end of OPTGROUP before start")
        self._optgroup = None
dataset/ETHPy150Open deanhiller/databus/webapp/play1.3.x/samples-and-tests/i-am-a-developer/mechanize/ClientForm.py/_AbstractFormParser.end_optgroup/operator `is` -> `is not`