def eos_token_id(self) -> Optional[int]:
        """
        `Optional[int]`: Id of the end of sentence token in the vocabulary. Returns `None` if the token has not been
        set.
        """
        if self._eos_token is None:
            return None
        return self.convert_tokens_to_ids(self.eos_token)

        `Optional[int]`: Id of the end of sentence token in the vocabulary. Returns `None` if the token has not been
        set.
        
dpkd/transformers/src/transformers/tokenization_utils_base.py