src/transformers/models/mmbt/modeling_mmbt.py/MMBTForClassification/__init__
class MMBTForClassification:    def __init__(self, config, transformer, encoder):
        super().__init__()
        self.num_labels = config.num_labels

        self.mmbt = MMBTModel(config, transformer, encoder)
        self.dropout = nn.Dropout(config.hidden_dropout_prob)
        self.classifier = nn.Linear(config.hidden_size, config.num_labels)