src/transformers/models/speech_to_text/tokenization_speech_to_text.py/Speech2TextTokenizer/save_vocabulary
class Speech2TextTokenizer:    def save_vocabulary(self, save_directory: str, filename_prefix: Optional[str] = None) -> Tuple[str]:
        save_dir = Path(save_directory)
        assert save_dir.is_dir(), f"{save_directory} should be a directory"
        vocab_save_path = save_dir / (
            (filename_prefix + "-" if filename_prefix else "") + self.vocab_files_names["vocab_file"]
        )
        spm_save_path = save_dir / (
            (filename_prefix + "-" if filename_prefix else "") + self.vocab_files_names["spm_file"]
        )

        save_json(self.encoder, vocab_save_path)

        if not spm_save_path.exists():
            copyfile(self.spm_file, spm_save_path)

        return (str(vocab_save_path), str(spm_save_path))