def build_inputs_with_special_tokens(
        self, token_ids_0: List[int], token_ids_1: Optional[List[int]] = None
    ) -> List[int]:
        """
        Build model inputs from a sequence or a pair of sequence for sequence classification tasks by concatenating and
        adding special tokens. The special tokens depend on calling set_lang.

        An SeamlessM4T sequence has the following format, where `X` represents the sequence:

        - `input_ids` (for encoder) `[src_lang_code] X [eos]`
        - `decoder_input_ids`: (for decoder) `[eos, tgt_lang_code] X [eos]`

        BOS is never used. Pairs of sequences are not the expected use case, but they will be handled without a
        separator.

        Args:
            token_ids_0 (`List[int]`):
                List of IDs to which the special tokens will be added.
            token_ids_1 (`List[int]`, *optional*):
                Optional second list of IDs for sequence pairs.

        Returns:
            `List[int]`: list of [input IDs](../glossary#input-ids) with the appropriate special tokens.
        """
        if token_ids_1 is None:
            return self.prefix_tokens + token_ids_0 + self.suffix_tokens
        # We don't expect to process pairs, but leave the pair logic for API consistency
        return self.prefix_tokens + token_ids_0 + token_ids_1 + self.suffix_tokens

        Build model inputs from a sequence or a pair of sequence for sequence classification tasks by concatenating and
        adding special tokens. The special tokens depend on calling set_lang.

        An SeamlessM4T sequence has the following format, where `X` represents the sequence:

        - `input_ids` (for encoder) `[src_lang_code] X [eos]`
        - `decoder_input_ids`: (for decoder) `[eos, tgt_lang_code] X [eos]`

        BOS is never used. Pairs of sequences are not the expected use case, but they will be handled without a
        separator.

        Args:
            token_ids_0 (`List[int]`):
                List of IDs to which the special tokens will be added.
            token_ids_1 (`List[int]`, *optional*):
                Optional second list of IDs for sequence pairs.

        Returns:
            `List[int]`: list of [input IDs](../glossary#input-ids) with the appropriate special tokens.
        
dpkd/transformers/src/transformers/models/seamless_m4t/tokenization_seamless_m4t_fast.py