models/pert_model.py

from transformers import BertForSequenceClassification, AdapterConfig

def get_pert_model(config):
    model = BertForSequenceClassification.from_pretrained('bert-base-uncased')
    adapter_config = AdapterConfig(mh_adapter=True, output_adapter=True, reduction_factor=config['model']['adapter']['reduction_factor'])
    model.add_adapter('imdb_adapter', config=adapter_config)
    model.train_adapter('imdb_adapter')
    return model