WatchlistRenamedEventArgs

 using cAlgo.API;
 namespace cAlgo
 {
     // This sample shows how to use WatchlistRenamedEventArgs
     [Indicator(IsOverlay = true, TimeZone = TimeZones.UTC, AccessRights = AccessRights.None)]
     public class WatchlistRenamedEventArgsSample : Indicator
     {
         protected override void Initialize()
         {
             Watchlists.WatchlistRenamed += OnWatchlistRenamed;
         }
         private void OnWatchlistRenamed(WatchlistRenamedEventArgs obj)
         {
             Print("Watchlist renamed to {0}", obj.Watchlist.Name);
         }
         public override void Calculate(int index)
         {
         }
     }
 }

 import clr
 clr.AddReference("cAlgo.API")
 from cAlgo.API import *
 class Test():    
     def initialize(self):
         api.Watchlists.WatchlistRenamed += self.on_watchlist_renamed
     def on_watchlist_renamed(self, args):
         print(f"Watchlist renamed to {args.Watchlist.Name}")