src/transformers/models/esm/tokenization_esm.py/EsmTokenizer/save_vocabulary
class EsmTokenizer:    def save_vocabulary(self, save_directory, filename_prefix):
        vocab_file = os.path.join(save_directory, (filename_prefix + "-" if filename_prefix else "") + "vocab.txt")
        with open(vocab_file, "w") as f:
            f.write("\n".join(self.all_tokens))
        return (vocab_file,)