Update app.py

app.py

@@ -13,7 +13,7 @@ from langchain_core.messages import HumanMessage, SystemMessage
 from langchain.chains import create_history_aware_retriever, create_retrieval_chain
 from langchain.chains.combine_documents import create_stuff_documents_chain
 from dotenv import load_dotenv, dotenv_values
-
+import os
 HUGGINGFACEHUB_API_TOKEN = os.getenv("HUGGINGFACEHUB_API_TOKEN")
 os.environ['HUGGINGFACEHUB_API_TOKEN'] = str(HUGGINGFACEHUB_API_TOKEN)
 GOOGLE_API_KEY = os.getenv("GOOGLE_API_KEY")