def GetOptions(self):
    """Retrieves descriptor options.

    This method returns the options set or creates the default options for the
    descriptor.
    """
    if self._options:
      return self._options

    from google.protobuf import descriptor_pb2
    try:
      options_class = getattr(descriptor_pb2,
                              self._options_class_name)
    except AttributeError:
      raise RuntimeError('Unknown options class name %s!' %
                         (self._options_class_name))

    with _lock:
      if self._serialized_options is None:
        self._options = options_class()
      else:
        self._options = _ParseOptions(options_class(),
                                      self._serialized_options)

      return self._options
Retrieves descriptor options.

    This method returns the options set or creates the default options for the
    descriptor.
    
deps/protobuf/python/google/protobuf/descriptor.py