Update app.py

app.py

@@ -1,11 +1,11 @@
 import openai
 import gradio as gr
 from langchain.chains import RetrievalQA
-from langchain.llms import openai
+from langchain.llms import OpenAI
 from langchain.document_loaders import PyPDFLoader
 from langchain.embeddings.openai import OpenAIEmbeddings
 from langchain.vectorstores import FAISS
-from langchain.chat_models import chatOpenAI
+from langchain.chat_models import ChatOpenAI
 from PyPDF import PdfReader