code: def test_barrier(self):
      multi_process_runner.run(
          fn_with_barrier,
          cluster_spec=multi_worker_test_base.create_cluster_spec(
              has_chief=True, num_workers=1
          ),
      )
  
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 12 for calling the MultiProcessRunnerTest obj's underlying member method code with example usage: obj.test_barrier() without return types