makechain.py

from langchain.chat_models import ChatOpenAI
from langchain.vectorstores.pinecone import Pinecone
import openai
from langchain.chains import RetrievalQAWithSourcesChain
import os
OPENAI_API_KEY = os.environ.get("OPENAI_API_KEY")
def get_chain(vectorstore: Pinecone):
    openai.api_key = OPENAI_API_KEY
    llm = ChatOpenAI(temperature=0, model_name="gpt-3.5-turbo")

    qa_chain = RetrievalQAWithSourcesChain.from_chain_type(llm=llm, chain_type="stuff",
                                                           retriever=vectorstore.as_retriever())

    return qa_chain