src/transformers/tokenization_utils_base.py/SpecialTokensMixin/additional_special_tokens_ids
class SpecialTokensMixin:    def additional_special_tokens_ids(self) -> List[int]:
        """
        :obj:`List[int]`: Ids of all the additional special tokens in the vocabulary. Log an error if used while not
        having been set.
        """
        return self.convert_tokens_to_ids(self.additional_special_tokens)