configuration.py

from transformers import GPT2Config

try:
    from configuration2 import OldModelConfig
except ImportError:
    from .configuration2 import OldModelConfig


class NewModelConfig(OldModelConfig):
    model_type = "new-model"
    
    def __init__(self, *args, new_hidden_size=12, **kwargs):
        super().__init__(*args, **kwargs)
        self.new_hidden_size = new_hidden_size