src/transformers/models/distilbert/modeling_distilbert.py/DistilBertForQuestionAnswering/__init__
class DistilBertForQuestionAnswering:    def __init__(self, config):
        super().__init__(config)

        self.distilbert = DistilBertModel(config)
        self.qa_outputs = nn.Linear(config.dim, config.num_labels)
        assert config.num_labels == 2
        self.dropout = nn.Dropout(config.qa_dropout)

        self.init_weights()