Update app.py

app.py

@@ -3,7 +3,7 @@ import tempfile
 from dotenv import load_dotenv
 import streamlit as st
 from langchain.embeddings.openai import OpenAIEmbeddings
-from openai.chat_models import ChatOpenAI
+from langchain.chat_models import ChatOpenAI
 from langchain.document_loaders import PyPDFLoader
 from langchain.text_splitter import RecursiveCharacterTextSplitter
 from langchain.schema import Document