code: def testOptionalSpec(self, tf_value_fn, expected_value_structure):
      tf_value = tf_value_fn()
      opt = optional_ops.Optional.from_value(tf_value)
  
      self.assertTrue(
          structure.are_compatible(
              opt.element_spec, expected_value_structure
          )
      )
  
      opt_structure = structure.type_spec_from_value(opt)
      self.assertIsInstance(opt_structure, optional_ops.OptionalSpec)
      self.assertTrue(
          structure.are_compatible(opt_structure, opt_structure)
      )
      self.assertTrue(
          structure.are_compatible(
              opt_structure._element_spec, expected_value_structure
          )
      )
      self.assertEqual(
          [dtypes.variant],
          structure.get_flat_tensor_types(opt_structure),
      )
      self.assertEqual(
          [tensor_shape.TensorShape([])],
          structure.get_flat_tensor_shapes(opt_structure),
      )
  
      # All OptionalSpec objects are not compatible with a non-optional
      # value.
      non_optional_structure = structure.type_spec_from_value(
          constant_op.constant(42.0)
      )
      self.assertFalse(
          opt_structure.is_compatible_with(non_optional_structure)
      )
  
      # Assert that the optional survives a round-trip via _from_tensor_list()
      # and _to_tensor_list().
      round_trip_opt = opt_structure._from_tensor_list(
          opt_structure._to_tensor_list(opt)
      )
      if isinstance(tf_value, optional_ops.Optional):
          self.assertValuesEqual(
              self.evaluate(tf_value.get_value()),
              self.evaluate(round_trip_opt.get_value().get_value()),
          )
      else:
          self.assertValuesEqual(
              self.evaluate(tf_value),
              self.evaluate(round_trip_opt.get_value()),
          )
  
imports: import functools
  from absl.testing import parameterized
  import numpy
  from tensorflow.python.data.kernel_tests import test_base
  from tensorflow.python.data.ops import dataset_ops
  from tensorflow.python.data.ops import iterator_ops
  from tensorflow.python.data.ops import optional_ops
  from tensorflow.python.data.util import structure
  from tensorflow.python.eager import context
  from tensorflow.python.eager import def_function
  from tensorflow.python.framework import combinations
  from tensorflow.python.framework import constant_op
  from tensorflow.python.framework import dtypes
  from tensorflow.python.framework import errors
  from tensorflow.python.framework import ops
  from tensorflow.python.framework import sparse_tensor
  from tensorflow.python.framework import tensor_shape
  from tensorflow.python.framework import tensor_spec
  from tensorflow.python.framework import test_util
  from tensorflow.python.ops import array_ops
  from tensorflow.python.ops import math_ops
  from tensorflow.python.platform import test
label_desc: Use image node_id 11 for calling the OptionalTest obj's underlying member method code with example usage: obj.testOptionalSpec(tf_value_fn, expected_value_structure) without return types