List subscribers of a list

        :param list_id: list ID number
        :return: :class:`~responsebot.models.User` object

def list_subscribers(self, list_id):
        """
        List subscribers of a list

        :param list_id: list ID number
        :return: :class:`~responsebot.models.User` object
        """
        return [User(user._json) for user in self._client.list_subscribers(list_id=list_id)]