src/transformers/models/visual_bert/modeling_visual_bert.py/VisualBertPreTrainingHeads/__init__
class VisualBertPreTrainingHeads:    def __init__(self, config):
        super().__init__()
        self.predictions = VisualBertLMPredictionHead(config)
        self.seq_relationship = nn.Linear(config.hidden_size, 2)