!python --version

Python 3.12.4

from constants import OPENAI_API_KEY

!pip show langchain-openai | grep "Version:"

Version: 0.2.9

import os

os.environ["OPENAI_API_KEY"] = OPENAI_API_KEY

from langchain_openai import ChatOpenAI

model = ChatOpenAI(model="gpt-4o-mini")

# https://python.langchain.com/docs/how_to/functions/

from langchain_core.output_parsers import StrOutputParser
from langchain_core.runnables import chain
from langchain_core.prompts import ChatPromptTemplate

prompt1 = ChatPromptTemplate.from_template("Tell me a joke about {topic}")
prompt2 = ChatPromptTemplate.from_template("What is the subject of this joke: {joke}")


@chain
def custom_chain(text):
    prompt_val1 = prompt1.invoke({"topic": text})
    output1 = ChatOpenAI().invoke(prompt_val1)

    parsed_output1 = StrOutputParser().invoke(output1)
    chain2 = prompt2 | ChatOpenAI() | StrOutputParser()

    return chain2.invoke({"joke": parsed_output1})

custom_chain.invoke("bears")

'The subject of the joke is the bear breaking up with his girlfriend.'