src/transformers/models/bridgetower/modeling_bridgetower.py/BridgeTowerMLMHead/__init__
class BridgeTowerMLMHead:    def __init__(self, config, weight=None):
        super().__init__()
        self.config = config
        self.transform = BridgeTowerPredictionHeadTransform(config)
        self.decoder = nn.Linear(config.hidden_size, config.text_config.vocab_size, bias=False)
        self.bias = nn.Parameter(torch.zeros(config.text_config.vocab_size))
        if weight is not None:
            self.decoder.weight = weight