diff --git a/Telegrator/Providers/HandlersCollection.cs b/Telegrator/Providers/HandlersCollection.cs
index 6a8c741..2f0f7f3 100644
--- a/Telegrator/Providers/HandlersCollection.cs
+++ b/Telegrator/Providers/HandlersCollection.cs
@@ -70,10 +70,10 @@ namespace Telegrator.Providers
             if (MustHaveParameterlessCtor && !descriptor.HandlerType.HasParameterlessCtor())
                 throw new Exception("This handler (" + descriptor.HandlerType.FullName + "), must contain constructor without parameters.");
 
-            _allowedTypes.Union(descriptor.UpdateType);
+            _allowedTypes.UnionAdd(descriptor.UpdateType);
             MightAwaitAttribute[] mightAwaits = descriptor.HandlerType.GetCustomAttributes<MightAwaitAttribute>().ToArray();
             if (mightAwaits.Length > 0)
-                _allowedTypes.Union(mightAwaits.SelectMany(attr => attr.UpdateTypes));
+                _allowedTypes.UnionAdd(mightAwaits.SelectMany(attr => attr.UpdateTypes));
 
             IntersectCommands(descriptor);
             HandlerDescriptorList list = GetDescriptorList(descriptor);
diff --git a/Telegrator/TypesExtensions.cs b/Telegrator/TypesExtensions.cs
index f0681b1..3acf39c 100644
--- a/Telegrator/TypesExtensions.cs
+++ b/Telegrator/TypesExtensions.cs
@@ -1019,7 +1019,7 @@ namespace Telegrator
         /// <typeparam name="TSource"></typeparam>
         /// <param name="list"></param>
         /// <param name="elements"></param>
-        public static void Union<TSource>(this IList<TSource> list, params IEnumerable<TSource> elements)
+        public static void UnionAdd<TSource>(this IList<TSource> list, params IEnumerable<TSource> elements)
         {
             foreach (TSource item in elements)
             {