Follow a user.

        :param user_id: ID of the user in question
        :return: The user that were unfollowed

def unfollow(self, user_id):
        """
        Follow a user.

        :param user_id: ID of the user in question
        :return: The user that were unfollowed
        """
        return User(self._client.destroy_friendship(user_id=user_id)._json)