diff --git a/MyPractice/Youtube/Server.cs b/MyPractice/Youtube/Server.cs
index 6d96fb1..98319fc 100644
--- a/MyPractice/Youtube/Server.cs
+++ b/MyPractice/Youtube/Server.cs
@@ -29,7 +29,7 @@ public void UploadFinished(object? sender, DataEventArgs e)
 	
 	private void SendNotification() 
 	{
-		if (notificationHandler != null) notificationHandler.Invoke(this, data);
+		notificationHandler?.Invoke(this, data);
 	}
 	
 	public void ViewReached(object? sender, DataEventArgs e) 
diff --git a/MyPractice/Youtube/Subscriber.cs b/MyPractice/Youtube/Subscriber.cs
index 6944e6a..50f99c7 100644
--- a/MyPractice/Youtube/Subscriber.cs
+++ b/MyPractice/Youtube/Subscriber.cs
@@ -27,9 +27,9 @@ public void WatchVideo(int videoIndex, int times)
 			{
 				_server.data.viewCount.Add(videoIndex, times);
 			}
-			if (_server.data.viewCount.GetValueOrDefault(videoIndex) >= _trendingThreshold && trendingHandler != null) 
+			if (_server.data.viewCount.GetValueOrDefault(videoIndex) >= _trendingThreshold) 
 			{
-				trendingHandler.Invoke(this, _server.data);	
+				trendingHandler?.Invoke(this, _server.data);	
 			}
 		}
 		else 
diff --git a/MyPractice/Youtube/Youtuber.cs b/MyPractice/Youtube/Youtuber.cs
index deaf51b..182a454 100644
--- a/MyPractice/Youtube/Youtuber.cs
+++ b/MyPractice/Youtube/Youtuber.cs
@@ -29,7 +29,7 @@ private void UploadToServer(int videoIndex, string videoTitle)
 	{
 		_server.data.videoIndex = videoIndex;
 		_server.data.videoTitle = videoTitle;
-		if (uploadHandler != null) uploadHandler.Invoke(this, _server.data);
+		uploadHandler?.Invoke(this, _server.data);
 	}
 	
 	public void WatchVideo(int videoIndex, int times) 
@@ -49,9 +49,9 @@ public void WatchVideo(int videoIndex, int times)
 				{
 					_server.data.viewCount.Add(videoIndex, times);
 				}
-				if (_server.data.viewCount.GetValueOrDefault(videoIndex) >= _server.TrendingThreshold && trendingHandler != null) 
+				if (_server.data.viewCount.GetValueOrDefault(videoIndex) >= _server.TrendingThreshold) 
 				{
-					trendingHandler.Invoke(this, _server.data);	
+					trendingHandler?.Invoke(this, _server.data);	
 				}
 			}
 		}