When a peft adapter has an invalid base model, how do I fix it?

fix_peft_local_invalid_base_model.py

peft_model_id = 'v2ray/GPT4chan-8B-QLoRA'

from transformers import AutoModelForCausalLM, AutoTokenizer, BitsAndBytesConfig, AutoConfig, LlamaConfig
from peft import PeftConfig, PeftModelForCausalLM

peft_config = PeftConfig.from_pretrained(peft_model_id)
# This model points to a local base model, which we don't have. So lets redirect it to a public version
peft_config.base_model_name_or_path="unsloth/Llama-3.1-8B"

# now load the modified config in 8bit
base_model = AutoModelForCausalLM.from_pretrained(
    peft_config.base_model_name_or_path,
    quantization_config=BitsAndBytesConfig(load_in_8bit=True)
)

# if the peft comes with an expanded embedding space
tokenizer = AutoTokenizer.from_pretrained(peft_model_id)
base_model.resize_token_embeddings(len(tokenizer))

# and add the adapter
model = PeftModelForCausalLM.from_pretrained(
    base_model,
    peft_model_id, 
    config=peft_config)