src/transformers/models/whisper/tokenization_whisper_fast.py/WhisperTokenizerFast/get_decoder_prompt_ids
class WhisperTokenizerFast:    def get_decoder_prompt_ids(self, task=None, language=None, no_timestamps=True):
        self.set_prefix_tokens(task=task, language=language, predict_timestamps=not no_timestamps)
        # prefix tokens are of the form: <|startoftranscript|> <|lang_id|> <|task|> <|notimestamps|>
        # we don't want to force the bos token at position 1, as this is the starting token
        # when we generate, so we slice the prefix tokens to: <|lang_id|> <|task|> <|notimestamps|>
        # to get the forced tokens
        forced_tokens = self.prefix_tokens[1:]
        forced_decoder_ids = [(rank + 1, token) for rank, token in enumerate(forced_tokens)]
        return forced_decoder_ids