message: Better parameter validation for tf.data.Dataset.from_generator
diff: @@ -813,12 +813,12 @@ class DatasetV2(collections_abc.Iterable, tracking_base.Trackable,
  if not all(
  isinstance(_, type_spec.TypeSpec)
  for _ in nest.flatten(output_signature)):
  - raise TypeError("All the elements of `output_siganture` must be "
  + raise TypeError("All the elements of `output_signature` must be "
  "`tf.TypeSpec` objects.")
  else:
  - if output_types is None and output_shapes is not None:
  - raise TypeError("`output_shapes` can not be used alone without "
  - "`output_types`")
  + if output_types is None:
  + raise TypeError("Either `output_signature` or `output_types` must "
  + "be specified")
  if output_signature is None:
  if output_shapes is None:
  