Update app.py

app.py

@@ -32,8 +32,8 @@ vectorstore.persist()
 qa = RetrievalQAWithSourcesChain.from_chain_type(
             llm=llm,
             chain_type="stuff",
-            #retriever=vectorstore.as_retriever(search_type="mmr"),
-            retriever=vectorstore.as_retriever(),
+            retriever=vectorstore.as_retriever(search_type="mmr"),
+            #retriever=vectorstore.as_retriever(),
             return_source_documents=True, 
             max_tokens_limit=4000
         )