Update app.py

app.py

@@ -61,7 +61,7 @@ if query:
     try:
         with open(file_path, "rb") as f:
             vectorstore = pickle.load(f)
-            chain = RetrievalQAWithSourcesChain.from_llm(llm=llm, retriever=vectorstore.as_retriever())
+            chain = RetrievalQAWithSourcesChain.from_llm(llm=llm, retriever=vector_store.as_retriever())
             result = chain({"question": query}, return_only_outputs=True)
             # result will be a dictionary of this format --> {"answer": "", "sources": [] }
             st.header("Answer")