code: def testReductionDistributed(
      self, required_gpus, use_strategy_object, bytes_per_pack
  ):
      hints = collective_util.Hints(bytes_per_pack=bytes_per_pack)
      self._run_between_graph_clients(
          self._test_reduction,
          self._cluster_spec,
          required_gpus,
          communication=CollectiveCommunication.RING,
          use_strategy_object=use_strategy_object,
          hints=hints,
      )
  
imports: import itertools
  import os
  import threading
  import time
  from absl.testing import parameterized
  import numpy
  from tensorflow.core.protobuf import config_pb2
  from tensorflow.python.distribute import cluster_resolver
  from tensorflow.python.distribute import collective_all_reduce_strategy
  from tensorflow.python.distribute import collective_util
  from tensorflow.python.distribute import combinations
  from tensorflow.python.distribute import cross_device_ops
  from tensorflow.python.distribute import cross_device_utils
  from tensorflow.python.distribute import device_util
  from tensorflow.python.distribute import distribute_utils
  from tensorflow.python.distribute import multi_worker_test_base
  from tensorflow.python.distribute import multi_worker_util
  from tensorflow.python.distribute import reduce_util
  from tensorflow.python.distribute import strategy_combinations
  from tensorflow.python.distribute import values
  from tensorflow.python.eager import context
  from tensorflow.python.eager import test
  from tensorflow.python.framework import constant_op
  from tensorflow.python.framework import indexed_slices
  from tensorflow.python.framework import kernels
  from tensorflow.python.framework import ops
  from tensorflow.python.framework import tensor
  from tensorflow.python.ops import array_ops
  from tensorflow.python.ops import collective_ops
  from tensorflow.python.ops import math_ops
  from tensorflow.python.ops import variables
label_desc: Use image node_id 8 for calling the CollectiveAllReduceTest obj's underlying member method code with example usage: obj.testReductionDistributed(required_gpus, use_strategy_object, bytes_per_pack) without return types