code: def testMirrored2CPUs(self, distribution):
      with distribution.scope():
          one_per_replica = distribution.run(
              lambda: constant_op.constant(1)
          )
          num_replicas = distribution.reduce(
              reduce_util.ReduceOp.SUM, one_per_replica, axis=None
          )
          self.assertEqual(2, self.evaluate(num_replicas))
  
imports: from absl.testing import parameterized
  from tensorflow.python import tf2
  from tensorflow.python.distribute import central_storage_strategy
  from tensorflow.python.distribute import collective_all_reduce_strategy
  from tensorflow.python.distribute import combinations
  from tensorflow.python.distribute import mirrored_strategy
  from tensorflow.python.distribute import one_device_strategy
  from tensorflow.python.distribute import parameter_server_strategy_v2
  from tensorflow.python.distribute import reduce_util
  from tensorflow.python.distribute import strategy_combinations
  from tensorflow.python.distribute import test_util
  from tensorflow.python.distribute import tpu_strategy
  from tensorflow.python.eager import def_function
  from tensorflow.python.framework import constant_op
  from tensorflow.python.ops import array_ops
  from tensorflow.python.platform import test
label_desc: Use image node_id 3 for calling the StrategyCombinationsTest obj's underlying member method code with example usage: obj.testMirrored2CPUs(distribution) without return types