ChartObjectsUpdatedEventArgs

 using cAlgo.API;
 namespace cAlgo
 {
     // This example shows how to use the Chart ChartObjectsUpdatedEventArgs
     // Draw an object, and then modify it
     [Indicator(IsOverlay = true, TimeZone = TimeZones.UTC, AccessRights = AccessRights.None)]
     public class ChartObjectsUpdatedEventArgsSample : Indicator
     {
         protected override void Initialize()
         {
             Chart.ObjectsUpdated += Chart_ObjectsUpdated;
         }
         private void Chart_ObjectsUpdated(ChartObjectsUpdatedEventArgs obj)
         {
             Print("Updated objects #: {0}", obj.ChartObjects.Count);
         }
         public override void Calculate(int index)
         {
         }
     }
 }

 import clr
 clr.AddReference("cAlgo.API")
 from cAlgo.API import *
 class Test():    
     def initialize(self):
         api.Chart.ObjectsUpdated += self.on_chart_Objects_updated
     def on_chart_Objects_updated(self, args):
         print(f"Updated objects #: {args.ChartObjects.Count}")