attempting to fix tracking pt issue

app.py

@@ -768,6 +768,10 @@ with gr.Blocks() as demo:
         
         print(tracking_points.constructor_args, tracking_points.constructor_args['value'])
 
+        tracking_point_values = tracking_points.constructor_args['value']
+        if len(tracking_point_values) == 0:
+            tracking_points.constructor_args['value'].append([])
+            
         tracking_points.constructor_args['value'][-1].append(evt.index)