code: def testSaveRestoreMultipleIterator(self, enable_async_ckpt):
      checkpoint_directory = self.get_temp_dir()
      checkpoint_prefix = os.path.join(checkpoint_directory, "ckpt")
      dataset = dataset_ops.Dataset.from_tensor_slices(
          [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11]
      )
      dataset = dataset.map(math_ops.square).batch(2)
      iterator_1 = iter(dataset)
      get_next_1 = iterator_1.get_next
      iterator_2 = iter(dataset)
      get_next_2 = iterator_2.get_next
      dataset_2 = dataset_ops.Dataset.range(10)
      iterator_3 = iter(dataset_2)
      get_next_3 = iterator_3.get_next
      ckpt_options = checkpoint_options.CheckpointOptions(
          experimental_enable_async_checkpoint=enable_async_ckpt
      )
      checkpoint = trackable_utils.Checkpoint(
          iterator_1=iterator_1,
          iterator_2=iterator_2,
          iterator_3=iterator_3,
      )
      self.assertAllEqual([1, 4], get_next_1())
      self.assertAllEqual(0, get_next_3())
      self.assertAllEqual(1, get_next_3())
      self.assertAllEqual(2, get_next_3())
      save_path = checkpoint.save(
          checkpoint_prefix, options=ckpt_options
      )
      self.assertAllEqual([1, 4], get_next_2())
      self.assertAllEqual([9, 16], get_next_2())
      self.assertAllEqual(3, get_next_3())
      checkpoint.restore(save_path).run_restore_ops()
      self.assertAllEqual([9, 16], get_next_1())
      self.assertAllEqual([1, 4], get_next_2())
      self.assertAllEqual(3, get_next_3())
  
imports: import os
  from absl.testing import parameterized
  from tensorflow.python.checkpoint import checkpoint
  from tensorflow.python.checkpoint import checkpoint_management
  from tensorflow.python.checkpoint import checkpoint_options
  from tensorflow.python.data.experimental.ops import grouping
  from tensorflow.python.data.experimental.ops import interleave_ops
  from tensorflow.python.data.experimental.ops import scan_ops
  from tensorflow.python.data.experimental.ops import take_while_ops
  from tensorflow.python.data.kernel_tests import test_base
  from tensorflow.python.data.ops import dataset_ops
  from tensorflow.python.data.ops import options
  from tensorflow.python.eager import test
  from tensorflow.python.framework import combinations
  from tensorflow.python.framework import dtypes
  from tensorflow.python.framework import errors
  from tensorflow.python.framework import ops
  from tensorflow.python.ops import gen_dataset_ops
  from tensorflow.python.ops import io_ops
  from tensorflow.python.ops import math_ops
  from tensorflow.python.ops import parsing_ops
  from tensorflow.python.ops import random_ops
  from tensorflow.python.ops import script_ops
  from tensorflow.python.ops import variables
  from tensorflow.python.platform import gfile
label_desc: Use image node_id 11 for calling the CheckpointTest obj's underlying member method code with example usage: obj.testSaveRestoreMultipleIterator(enable_async_ckpt) without return types