src/transformers/models/big_bird/modeling_big_bird.py/BigBirdAttention/__init__
class BigBirdAttention:    def __init__(self, config, seed=None):
        super().__init__()
        self.attention_type = config.attention_type
        self.config = config
        self.seed = seed

        if self.config.attention_type == "original_full":
            self.self = BigBirdSelfAttention(config)
        elif self.config.attention_type == "block_sparse":
            self.self = BigBirdBlockSparseAttention(config, seed)
        else:
            raise ValueError(
                f"attention_type can either be original_full or block_sparse, but is {self.config.attention_type}"
            )

        self.output = BigBirdSelfOutput(config)