code: def add_task(self, subject, status, **attrs):
          
          return Tasks(self.requester).create(
              self.project, subject, status,
              user_story=self.id, **attrs
          )
docs: Add a :class:`Task` to the current :class:`UserStory` and return it.
          :param subject: subject of the :class:`Task`
          :param status: status of the :class:`Task`
          :param attrs: optional attributes for :class:`Task`