custom_model.py

from transformers import PreTrainedModel, BertConfig, AutoModel


class Model(PreTrainedModel):
    config_class = BertConfig

    def __init__(self, config):
        super().__init__(config)
        self.model = AutoModel.from_pretrained("bert-base-uncased")

    def forward(self, **inputs):
        outs = self.model(**inputs)
        return outs