code: def tearDownClass(cls):
      cls._channel.close()
      cls._server.stop(None)
      super().tearDownClass()
  
file_path: tfx/tfx/orchestration/experimental/centralized_kubernetes_orchestrator/service/kubernetes_orchestrator_service_test.py
imports: from unittest import mock
  import grpc
  from grpc.framework.foundation import logging_pool
  import portpicker
  import tensorflow
  from tfx.orchestration.experimental.centralized_kubernetes_orchestrator.service import kubernetes_orchestrator_service
  from tfx.orchestration.experimental.centralized_kubernetes_orchestrator.service.proto import service_pb2
  from tfx.orchestration.experimental.centralized_kubernetes_orchestrator.service.proto import service_pb2_grpc
  from tfx.orchestration.experimental.core import pipeline_ops
  from tfx.orchestration.experimental.core import task
  from tfx.proto.orchestration import pipeline_pb2
  from tfx.utils import status
label_desc: Use image node_id 2 for calling the KubernetesOrchestratorServiceTest obj's underlying member method code with example usage: obj.tearDownClass(cls) without return types