code: def test_barrier_called_in_main_process(self):
      with self.assertRaises(ValueError):
          multi_process_runner.get_barrier()
  
imports: import ctypes
  import json
  import os
  import sys
  import threading
  import time
  import unittest
  from absl import logging
  from absl.testing import parameterized
  from tensorflow.python.distribute import combinations
  from tensorflow.python.distribute import multi_process_runner
  from tensorflow.python.distribute import multi_worker_test_base
  from tensorflow.python.eager import context
  from tensorflow.python.eager import test
label_desc: Use image node_id 13 for calling the MultiProcessRunnerTest obj's underlying member method code with example usage: obj.test_barrier_called_in_main_process() without return types