def add_list_member(self, list_id, user_id):
        """
        Add a user to list

        :param list_id: list ID number
        :param user_id: user ID number
        :return: :class:`~responsebot.models.List` object
        """
        return List(tweepy_list_to_json(self._client.add_list_member(list_id=list_id, user_id=user_id)))