code: def take_notification(self, block=True, timeout=None):
          
          return self._session.take_notification(block, timeout)
docs: Attempt to retrieve one notification from the queue of received
          notifications.
  
          If block is True, the call will wait until a notification is
          received.
  
          If timeout is a number greater than 0, the call will wait that
          many seconds to receive a notification before timing out.
  
          If there is no notification available when block is False or
          when the timeout has elapse, None will be returned.
  
          Otherwise a :class:`~ncclient.operations.notify.Notification`
          object will be returned.