src/transformers/models/bert_generation/modeling_bert_generation.py/BertGenerationOnlyLMHead/__init__
class BertGenerationOnlyLMHead:    def __init__(self, config):
        super().__init__()
        self.decoder = nn.Linear(config.hidden_size, config.vocab_size)
        self.bias = nn.Parameter(torch.zeros(config.vocab_size))
        self.decoder.bias = self.bias