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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, ignore_warnings=None):
 """Update this app_profile. .. note:: Update any or all of the following values: ``routing_policy_type`` ``description`` ``cluster_id`` ``allow_transactional_writes`` """

        update_mask_pb = field_mask_pb2.FieldMask()

        if self.description is not None:
            update_mask_pb.paths.append("description")

        if self.routing_policy_type == RoutingPolicyType.ANY:
            update_mask_pb.paths.append("multi_cluster_routing_use_any")
        else:
            update_mask_pb.paths.append("single_cluster_routing")

        return self.instance_admin_client.update_app_profile(
            app_profile=self._to_pb(),
            update_mask=update_mask_pb,
            ignore_warnings=ignore_warnings,
        )