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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def update(self, new_lease_time, client=None):
 """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`). """

        return self.taskqueue.update_task(self.id, new_lease_time=new_lease_time, client=client)