class_docstr: Concrete implementation of `tf.experimental.Optional`.
  
  NOTE(mrry): This implementation is kept private, to avoid defining
  `Optional.__init__()` in the public API.
code: def __init__(self, variant_tensor, element_spec):
      super().__init__()
      self._variant_tensor = variant_tensor
      self._element_spec = element_spec
  
imports: import abc
  from tensorflow.core.protobuf import struct_pb2
  from tensorflow.python.data.util import structure
  from tensorflow.python.framework import composite_tensor
  from tensorflow.python.framework import dtypes
  from tensorflow.python.framework import ops
  from tensorflow.python.framework import tensor_spec
  from tensorflow.python.framework import type_spec
  from tensorflow.python.ops import gen_optional_ops
  from tensorflow.python.saved_model import nested_structure_coder
  from tensorflow.python.util import deprecation
  from tensorflow.python.util.tf_export import tf_export
label_desc: Use image node_id 1 to create a new _OptionalImpl object from inherited base classes: Optional with example: obj = _OptionalImpl(variant_tensor, element_spec)