message: Renaming register serialization from module to package.
diff: @@ -143,7 +143,7 @@ def register_keras_serializable(package='Custom', name=None):
  Note that to be serialized and deserialized, classes must implement the
  `get_config()` method. Functions do not have this requirement.
  - The object will be registered under the key 'module>name' where `name`,
  + The object will be registered under the key 'package>name' where `name`,
  defaults to the object name if not passed.
  Arguments:
  