code: def testCollectiveV2ControlFlow(
      self, num_processes, required_gpus, implementation
  ):
      def replica_fn():
          CollectiveReplicaLauncher._prefer_unique_instance_key = True
          collective, devices, _ = self.make_collective(
              num_processes, required_gpus
          )
          options = collective_util.Options(
              implementation=implementation
          )
          value = make_per_replica_value(
              constant_op.constant([1.0]), devices
          )
  
          @def_function.function
          def reduce_fn():
              def cond_body():
                  reduced = collective.reduce(
                      reduce_util.ReduceOp.SUM, value, value, options
                  )
                  return math_ops.add_n(self.as_list(reduced)) / len(
                      devices
                  )
  
              return cond.cond(
                  array_ops.identity(False), cond_body, cond_body
              )
  
          num_replicas = num_processes * len(devices)
          self.assertAllEqual(reduce_fn(), [1.0 * num_replicas])
  
      get_global_mpr(num_processes).run(replica_fn)
  
imports: import collections
  import os
  import threading
  import time
  from absl.testing import parameterized
  from tensorflow.core.protobuf import config_pb2
  from tensorflow.core.protobuf import tensorflow_server_pb2
  from tensorflow.python.distribute import cluster_resolver
  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 multi_process_runner
  from tensorflow.python.distribute import multi_worker_test_base
  from tensorflow.python.distribute import reduce_util
  from tensorflow.python.distribute import test_util
  from tensorflow.python.distribute import values
  from tensorflow.python.eager import context
  from tensorflow.python.eager import def_function
  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 indexed_slices
  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 cond
  from tensorflow.python.ops import math_ops
  from tensorflow.python.util import nest
label_desc: Use image node_id 16 for calling the CollectiveOpsTest obj's underlying member method code with example usage: obj.testCollectiveV2ControlFlow(num_processes, required_gpus, implementation) and returns: cond, unknown