code: def testStartMultipleTimesFail(self):
      # Prepare mocks and variables.
      runner = self._create_local_docker_runner()
  
      # Act.
      runner.Start()
      with self.assertRaises(AssertionError) as err:
          runner.Start()
  
      # Check errors.
      self.assertEqual(
          str(err.exception),
          "You cannot start model server multiple times.",
      )
  
imports: import os
  from typing import Any, Dict
  from unittest import mock
  from docker import errors
  import tensorflow
  from tfx.components.infra_validator import error_types
  from tfx.components.infra_validator import serving_bins
  from tfx.components.infra_validator.model_server_runners import local_docker_runner
  from tfx.proto import infra_validator_pb2
  from tfx.types import standard_artifacts
  from tfx.utils import path_utils
  from google.protobuf import json_format
label_desc: Use image node_id 4 for calling the LocalDockerRunnerTest obj's underlying member method code with example usage: obj.testStartMultipleTimesFail() without return types