Update app.py

app.py

@@ -7,7 +7,7 @@ from langchain.chains import ConversationalRetrievalChain
 from langchain.text_splitter import RecursiveCharacterTextSplitter
 from langchain.memory import ConversationBufferMemory
 from langchain_community.document_loaders import PyPDFLoader
-
+import os
 load_dotenv()
 
 # Get the Hugging Face API token from the .env file