def METHOD_NAME(self, save_directory: str, filename_prefix: Optional[str] = None) -> Tuple[str]:
    if not os.path.isdir(save_directory):
        logger.error(f"Vocabulary path ({save_directory}) should be a directory")
        return
    out_vocab_file = os.path.join(
        save_directory, (filename_prefix + "-" if filename_prefix else "") + VOCAB_FILES_NAMES["vocab_file"]
    )
    if os.path.abspath(self.vocab_file) != os.path.abspath(out_vocab_file) and os.path.isfile(self.vocab_file):
        copyfile(self.vocab_file, out_vocab_file)
    elif not os.path.isfile(self.vocab_file):
        with open(out_vocab_file, "wb") as fi:
            content_spiece_model = self.sp_model.serialized_model_proto()
            fi.write(content_spiece_model)
    return (out_vocab_file,)