src/transformers/models/vilt/modeling_vilt.py/ViltForQuestionAnswering/__init__
class ViltForQuestionAnswering:    def __init__(self, config):
        super().__init__(config)

        self.num_labels = config.num_labels
        self.vilt = ViltModel(config)

        # Classifier head
        self.classifier = nn.Sequential(
            nn.Linear(config.hidden_size, config.hidden_size * 2),
            nn.LayerNorm(config.hidden_size * 2),
            nn.GELU(),
            nn.Linear(config.hidden_size * 2, config.num_labels),
        )

        # Initialize weights and apply final processing
        self.post_init()