code: def testElementSpecOptional(self):
      range_dataset = dataset_ops.Dataset.range(42)
      dict_dataset = dataset_ops.Dataset.from_tensor_slices(
          {"a": [1, 2], "b": [3, 4]}
      )
      tuple_dataset = dataset_ops.Dataset.from_tensor_slices(
          ([1, 2], [3, 4])
      )
      dataset = dataset_ops.Dataset.zip(
          (range_dataset, dict_dataset, tuple_dataset)
      )
      self.evaluate(dataset.save(self._test_dir))
      dataset_loaded = dataset_ops.Dataset.load(self._test_dir)
      self.assertDatasetsEqual(dataset, dataset_loaded)
  
imports: import os
  import shutil
  from absl.testing import parameterized
  import numpy
  from tensorflow.python.data.kernel_tests import checkpoint_test_base
  from tensorflow.python.data.kernel_tests import test_base
  from tensorflow.python.data.ops import dataset_ops
  from tensorflow.python.eager import def_function
  from tensorflow.python.framework import combinations
  from tensorflow.python.ops import variables
  from tensorflow.python.platform import test
label_desc: Use image node_id 8 for calling the IOTest obj's underlying member method code with example usage: obj.testElementSpecOptional() without return types