code: def testIterSingleInput(self, is_graph):
      dataset = dataset_ops.DatasetV2.from_tensors(self.images).repeat()
      batch_size = 32
      images_layout = Layout.batch_sharded(
          self.mesh, batch_dim=MESH_DIM_BATCH, rank=4
      )
  
      d_dataset = input_util.DTensorDataset(
          dataset=dataset,
          global_batch_size=batch_size,
          mesh=self.mesh,
          layouts=images_layout,
          batch_dim=MESH_DIM_BATCH,
      )
  
      self.assertEqual(
          d_dataset.element_spec.shape, [batch_size, 8, 8, 3]
      )
  
      def train(iterator):
          it = next(iterator)
          return it
  
      train_fn = (
          polymorphic_function.function(train) if is_graph else train
      )
  
      d_iterator = iter(d_dataset)
      self.assertEqual(
          d_iterator.element_spec.shape, [batch_size, 8, 8, 3]
      )
  
      d_images = train_fn(d_iterator)
      mesh_util.barrier(self.mesh)
      expected = next(
          iter(dataset.batch(batch_size, drop_remainder=True))
      )
      mesh_util.barrier(self.mesh)
      self.assertDTensorEqual(expected, images_layout, d_images)
  
imports: import contextlib
  import threading
  from absl.testing import parameterized
  import numpy
  from tensorflow.dtensor.python import api
  from tensorflow.dtensor.python import input_util
  from tensorflow.dtensor.python import layout
  from tensorflow.dtensor.python import mesh_util
  from tensorflow.dtensor.python.tests import test_util
  from tensorflow.python.data.ops import dataset_ops
  from tensorflow.python.eager.polymorphic_function import polymorphic_function
  from tensorflow.python.framework import constant_op
  from tensorflow.python.framework import dtypes
  from tensorflow.python.framework import errors_impl
  from tensorflow.python.framework import tensor_shape
  from tensorflow.python.framework import tensor_spec
  from tensorflow.python.ops import math_ops
  from tensorflow.python.ops import stateless_random_ops
  from tensorflow.python.ops import variables
  from tensorflow.python.platform import test
label_desc: Use image node_id 8 for calling the DTensorDatasetTest obj's underlying member method code with example usage: obj.testIterSingleInput(is_graph) and returns: it