code: def testAsyncCheckpointing(
      self, distribution, synchronization, aggregation, mode
  ):
      if (
          isinstance(
              distribution,
              collective_all_reduce_strategy.CollectiveAllReduceStrategy,
          )
          and mode == "graph"
      ):
          self.skipTest(
              "MWMS combinations tests do not work well in graph mode."
          )
  
      checkpoint_test_helper(
          self,
          distribution,
          synchronization,
          aggregation,
          enable_async_ckpt=True,
      )
  
imports: import copy
  import os
  from absl.testing import parameterized
  from tensorflow.python.checkpoint import checkpoint
  from tensorflow.python.checkpoint import checkpoint_options
  from tensorflow.python.distribute import collective_all_reduce_strategy
  from tensorflow.python.distribute import combinations
  from tensorflow.python.distribute import distribute_lib
  from tensorflow.python.distribute import distribute_utils
  from tensorflow.python.distribute import packed_distributed_variable
  from tensorflow.python.distribute import parameter_server_strategy
  from tensorflow.python.distribute import ps_values
  from tensorflow.python.distribute import strategy_combinations
  from tensorflow.python.distribute import test_util
  from tensorflow.python.distribute import tpu_strategy
  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 indexed_slices
  from tensorflow.python.framework import ops
  from tensorflow.python.framework import tensor_shape
  from tensorflow.python.ops import array_ops
  from tensorflow.python.ops import check_ops
  from tensorflow.python.ops import control_flow_assert
  from tensorflow.python.ops import math_ops
  from tensorflow.python.ops import variable_scope
  from tensorflow.python.ops import variables
  from tensorflow.python.saved_model import save
  from tensorflow.python.saved_model import save_context
  from tensorflow.python.saved_model import save_options
  from tensorflow.python.types import core
label_desc: Use image node_id 3 for calling the DistributedVariableTest obj's underlying member method code with example usage: obj.testAsyncCheckpointing(distribution, synchronization, aggregation, mode) without return types