Gets user information by user id

        Args:
            user_id(int): the id of user

        Returns:
            User

        Throws:
            RTMServiceError when request failed

def info(self, user_id):
        """Gets user information by user id

        Args:
            user_id(int): the id of user

        Returns:
            User

        Throws:
            RTMServiceError when request failed
        """
        resp = self._rtm_client.get('v1/user.info?user_id={}'.format(user_id))
        if resp.is_fail():
            raise RTMServiceError('Failed to get user information', resp)

        return resp.data['result']