Update app.py

app.py

@@ -459,11 +459,13 @@ if page == "Document, Retriever, Web Scraping Config":
     st.session_state['chunk_size'] = st.selectbox(
         "Chunk Size", 
         options=[500, 600, 700, 800, 900, 1000, 1250, 1500, 1750, 2000, 2250, 2500, 2750, 3000], 
-        key="chunk_size").on_change(get_retrievers)
+        on_change=get_retrievers,
+        key="chunk_size")
     st.session_state['chunk_overlap'] = st.selectbox(
         "Chunk Overlap", 
         options=[50, 100, 150, 200],
-         key="chunk_overlap").on_change(get_retrievers)
+        on_change=get_retrievers,
+         key="chunk_overlap")
 
 
 ################################ Main Chatbot Page ################################