chain.py

import os
# from dotenv import load_dotenv
# load_dotenv()
#os.environ['OPENAI_API_KEY'] = os.getenv("OPENAI_API_KEY")

OPENAI_API_KEY = os.environ['OPENAI_API_KEY']
from langchain.chat_models import ChatOpenAI
from langchain.prompts import ChatPromptTemplate
from langchain_core.output_parsers import StrOutputParser
from langchain_core.runnables import RunnablePassthrough


def my_chain(retriever,question):
    template = """Answer the question based only on the following context:
    {context}
    Question: {question}
    """
    prompt = ChatPromptTemplate.from_template(template)

    llm = ChatOpenAI(
        model_name="gpt-3.5-turbo", temperature=0, streaming=True
    )

    chain = (
        {"context": retriever, "question": RunnablePassthrough()}
        | prompt
        | llm
        | StrOutputParser()
    )
    answer=chain.invoke(question)
    return answer