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

        if config.is_decoder:
            logger.warning(
                "If you want to use `BigBirdForMaskedLM` make sure `config.is_decoder=False` for "
                "bi-directional self-attention."
            )

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

        self.init_weights()