Update app.py

app.py

@@ -12,7 +12,6 @@ from PyPDF2 import PdfReader, PdfWriter
 
 
 from langchain.chains import LLMChain, RetrievalQA
-from langchain_openai import ChatOpenAI
 from langchain.document_loaders import PyPDFLoader, WebBaseLoader, UnstructuredWordDocumentLoader, DirectoryLoader
 from langchain.document_loaders.blob_loaders.youtube_audio import YoutubeAudioLoader
 from langchain.document_loaders.generic import GenericLoader