message: Massage docstring for signatures arg of tf.saved_model.save. Previous wording minimized the dictionary option.
diff: @@ -960,14 +960,15 @@ def save(obj, export_dir, signatures=None, options=None):
  Args:
  obj: A trackable object to export.
  export_dir: A directory in which to write the SavedModel.
  - signatures: Optional, either a `tf.function` with an input signature
  - specified or the result of `f.get_concrete_function` on a
  - `@tf.function`-decorated function `f`, in which case `f` will be used to
  - generate a signature for the SavedModel under the default serving
  - signature key. `signatures` may also be a dictionary, in which case it
  - maps from signature keys to either `tf.function` instances with input
  - signatures or concrete functions. The keys of such a dictionary may be
  - arbitrary strings, but will typically be from the
  + signatures: Optional, one of three types:
  + * a `tf.function` with an input signature specified, which will use the
  + default serving signature key,
  + * the result of `f.get_concrete_function` on a `@tf.function`-decorated
  + function `f`, in which case `f` will be used to generate a signature for
  + the SavedModel under the default serving signature key,
  + * a dictionary, which maps signature keys to either `tf.function`
  + instances with input signatures or concrete functions. Keys of such a
  + dictionary may be arbitrary strings, but will typically be from the
  `tf.saved_model.signature_constants` module.
  options: Optional, `tf.saved_model.SaveOptions` object that specifies
  options for saving.
  