def mapper(features, *args):
    features.update(self._preprocess_fids(features.pop('fids'), slot_configs))
    return (((features,) + args) if args else features)
def mapper(features, *args):
    features.update(self._preprocess_fids(features.pop('fids'), slot_configs))
    return (((features,) + args) if args else features)