diff --git a/Jellyfin.Plugin.SmartPlaylist/Lisp/Interpreter.cs b/Jellyfin.Plugin.SmartPlaylist/Lisp/Interpreter.cs
index 76d0fbf..e72a4bd 100644
--- a/Jellyfin.Plugin.SmartPlaylist/Lisp/Interpreter.cs
+++ b/Jellyfin.Plugin.SmartPlaylist/Lisp/Interpreter.cs
@@ -65,7 +65,7 @@ namespace Jellyfin.Plugin.SmartPlaylist.Lisp {
             return null;
         }
         public void Set(string k, Expression v) {
-            Add(k, v);
+            this[k] = v;
         }
 
         public IEnvironment<string, Expression>? Find(string k) {