def __missing__(self, key):
        if self.default_factory is None:
            raise KeyError(key)
        else:
            ret = self[key] = self.default_factory(name=key)
            return ret
def check_prereq(self, prereqMode = 0):
        self._exit_modes_beyond(prereqMode)
        if len(self.modeList) <= prereqMode:
            raise Exception("Attempted to enter menu when prerequist mode was not entered, expected: %d" % prereqMode)