code: def update(self, new_lease_time, client=None):
          
          return self.taskqueue.update_task(self.id, new_lease_time=new_lease_time, client=client)
docs: Update the duration of a task lease
  
          :type new_lease_time: int
          :param new_lease_time: the new lease time in seconds.
  
          :type client: :class:`gcloud.taskqueue.client.Client` or ``NoneType``
          :param client: Optional. The client to use.  If not passed, falls back
                         to the ``client`` stored on the task's taskqueue.
  
          :rtype: :class:`Task`
          :returns: The task that was just updated.
          :raises: :class:`gcloud.exceptions.NotFound`
                   (propagated from
                   :meth:`gcloud.taskqueue.taskqueue.Taskqueue.update_task`).