code: def update(self, client=None, unique_writer_identity=False):
          
          client = self._require_client(client)
          resource = client.sinks_api.sink_update(
              self.project,
              self.name,
              self.filter_,
              self.destination,
              unique_writer_identity=unique_writer_identity,
          )
          self._update_from_api_repr(resource)
docs: API call:  update sink configuration via a PUT request
  
          See
          https://cloud.google.com/logging/docs/reference/v2/rest/v2/projects.sinks/update
  
          :type client: :class:`~google.cloud.logging.client.Client` or
                        ``NoneType``
          :param client: the client to use.  If not passed, falls back to the
                         ``client`` stored on the current sink.
  
          :type unique_writer_identity: bool
          :param unique_writer_identity: (Optional) determines the kind of
                                      IAM identity returned as
                                      writer_identity in the new sink.