class_docstr: Wraps a `tf.distribute.Strategy` and adds a name for test titles.
class_docstr_tok: ["Wraps","a","`","tf.distribute.Strategy","`","and","adds","a","name","for","test","titles","."]
code: def runner(self):
      if self._pool_runner_fn is not None:
          return self._pool_runner_fn()
      return None
  
imports: import collections
  import copy
  import re
  import sys
  import types
  import unittest
  from absl import app
  import six
  from tensorflow.python.client import session
  from tensorflow.python.distribute import collective_all_reduce_strategy
  from tensorflow.python.distribute import distribute_lib
  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 def_function
  from tensorflow.python.framework import combinations
  from tensorflow.python.framework import config
  from tensorflow.python.framework import ops
  from tensorflow.python.framework import test_combinations
  from tensorflow.python.framework import test_util
  from tensorflow.python.platform import flags
  from tensorflow.python.platform import tf_logging
  from tensorflow.python.util import tf_decorator
  from tensorflow.python.util import tf_inspect
  from tensorflow.python.util.tf_export import tf_export
label_desc: Use image node_id 2 for calling the NamedDistribution obj's underlying member method code with example usage: obj.runner() and returns: None, self