code: def testCheckHealth(self):
      def worker_fn():
          enable_collective_ops(
              cluster_resolver_lib.TFConfigClusterResolver()
          )
          # There may be some delays before the server startup. Check health should
          # eventually be OK.
          while True:
              try:
                  for task in [
                      "/job:worker/replica:0/task:0",
                      "/job:worker/replica:0/task:1",
                  ]:
                      context.context().check_collective_ops_peer_health(
                          task, timeout_in_ms=1000
                      )
              except (
                  errors.UnavailableError,
                  errors.DeadlineExceededError,
              ):
                  continue
              break
          multi_process_runner.get_barrier().wait()
  
      cluster_spec = multi_worker_test_base.create_cluster_spec(
          num_workers=2
      )
      mpr = multi_process_runner.MultiProcessRunner(
          worker_fn, cluster_spec
      )
      mpr.start()
      mpr.join()
  
imports: import copy
  import os
  import threading
  import time
  from absl.testing import parameterized
  from tensorflow.core.protobuf import tensorflow_server_pb2
  from tensorflow.python.distribute import cluster_resolver
  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
  from tensorflow.python.framework import constant_op
  from tensorflow.python.framework import dtypes
  from tensorflow.python.framework import errors
  from tensorflow.python.framework import ops
  from tensorflow.python.ops import collective_ops
label_desc: Use image node_id 1 for calling the CollectiveOpTest obj's underlying member method code with example usage: obj.testCheckHealth() without return types