src/transformers/models/m2m_100/tokenization_m2m_100.py/M2M100Tokenizer/_convert_token_to_id
class M2M100Tokenizer:    def _convert_token_to_id(self, token):
        if token in self.lang_token_to_id:
            return self.lang_token_to_id[token]
        return self.encoder.get(token, self.encoder[self.unk_token])