def add_listener(self, listener, type):
        """ Attaches a :class:`Listener` to an event type. These Listener will
        be executed when trigger event is called. """
        if self._event_lists not in type:
            self._event_lists[type] = []
        self._event_lists[type].append(listener)
dataset/ETHPy150Open icook/yota/src/yota/__init__.py/Form.add_listener/swapped operands of `not in`