src/transformers/models/splinter/tokenization_splinter_fast.py/SplinterTokenizerFast/save_vocabulary
class SplinterTokenizerFast:    def save_vocabulary(self, save_directory: str, filename_prefix: Optional[str] = None) -> Tuple[str]:
        files = self._tokenizer.model.save(save_directory, name=filename_prefix)
        return tuple(files)