src/transformers/models/big_bird/modeling_big_bird.py/BigBirdForCausalLM/__init__
class BigBirdForCausalLM:    def __init__(self, config):
        super().__init__(config)

        if not config.is_decoder:
            logger.warning("If you want to use `BigBirdForCausalLM` as a standalone, add `is_decoder=True.`")

        self.bert = BigBirdModel(config)
        self.cls = BigBirdOnlyMLMHead(config)

        # Initialize weights and apply final processing
        self.post_init()