class_docstr: tf.data service cluster with dispatcher and workers as subprocesses.
  
  To run the cluster in co-located mode, set `num_workers` to 0 and create the
  tf.data service workers manually in each client process.
code: def worker_addresses(self):
      return self._worker_addresses
  
imports: import os
  from typing import Any, List, Mapping, Optional, Tuple
  from absl import logging
  from absl.testing import parameterized
  import numpy
  from tensorflow.core.example import example_pb2
  from tensorflow.core.example import feature_pb2
  from tensorflow.dtensor.python import accelerator_util
  from tensorflow.dtensor.python import api
  from tensorflow.dtensor.python import config
  from tensorflow.dtensor.python import input_util
  from tensorflow.dtensor.python import layout
  from tensorflow.dtensor.python import mesh_util
  from tensorflow.dtensor.python.tests import multi_client_test_util
  from tensorflow.dtensor.python.tests import test_backend_util
  from tensorflow.dtensor.python.tests import test_util
  from tensorflow.python.data.experimental.service import server_lib
  from tensorflow.python.data.ops import dataset_ops
  from tensorflow.python.data.ops import readers
  from tensorflow.python.eager import context
  from tensorflow.python.framework import config
  from tensorflow.python.framework import device_spec
  from tensorflow.python.framework import dtypes
  from tensorflow.python.lib.io import tf_record
  from tensorflow.python.ops import array_ops_stack
  from tensorflow.python.ops import check_ops
  from tensorflow.python.ops import gen_parsing_ops
  from tensorflow.python.ops import io_ops
  from tensorflow.python.ops import parsing_config
  from tensorflow.python.ops import parsing_ops
  from tensorflow.python.ops import stateless_random_ops
  from tensorflow.python.platform import test
label_desc: Use image node_id 6 for calling the TFDataServiceCluster obj's underlying member method code with example usage: obj.worker_addresses() and returns: self