PEFT How to use TFLai/gpt2-medium-4bit-alpaca with PEFT:
from peft import PeftModel
from transformers import AutoModelForCausalLM
base_model = AutoModelForCausalLM.from_pretrained("gpt2-medium")
model = PeftModel.from_pretrained(base_model, "TFLai/gpt2-medium-4bit-alpaca") 
