code: def _testMultipleConcurrentCollectiveReduce(self, t0, t1, expected):
      group_key = 1
      group_size = 2
      num_instances = 2
      all_reduces = []
      config = config_pb2.ConfigProto(device_count={"CPU": group_size})
      config.experimental.collective_deterministic_sequential_execution = (
          True
      )
      with self.session(config=config) as sess:
          for cpu in range(group_size):
              with ops.device("/CPU:%d" % cpu):
                  in_tensor = constant_op.constant(
                      t0 if cpu == 0 else t1
                  )
                  for instance in range(num_instances):
                      all_reduces.append(
                          collective_ops.all_reduce(
                              in_tensor,
                              group_size,
                              group_key,
                              instance,
                              "Add",
                              "Div",
                          )
                      )
          results = sess.run(all_reduces)
      for i in range(group_size * num_instances):
          self.assertAllClose(
              results[i], expected, rtol=1e-5, atol=1e-5
          )
  
imports: import time
  from tensorflow.core.protobuf import config_pb2
  from tensorflow.core.protobuf import rewriter_config_pb2
  from tensorflow.python.eager import context
  from tensorflow.python.eager import def_function
  from tensorflow.python.framework import config
  from tensorflow.python.framework import constant_op
  from tensorflow.python.framework import dtypes
  from tensorflow.python.framework import errors
  from tensorflow.python.framework import kernels
  from tensorflow.python.framework import ops
  from tensorflow.python.framework import test_util
  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 variable_v1
  from tensorflow.python.ops import variables
  from tensorflow.python.ops import while_loop
  from tensorflow.python.platform import test
  from tensorflow.python.platform import tf_logging
label_desc: Use image node_id 3 for calling the CollectiveOpTest obj's underlying member method code with example usage: obj._testMultipleConcurrentCollectiveReduce(t0, t1, expected) without return types