Update app.py

app.py

@@ -124,8 +124,8 @@ with gr.Blocks() as demo:
     cart_button.click(cart_page, outputs=[cart_display, menu_display])
     
     # Render menu and cart
-    demo += menu_display
-    demo += cart_display
-    demo += notification
+    demo.append(menu_display)
+    demo.append(cart_display)
+    demo.append(notification)
 
 demo.launch()