diff --git a/lib/extension/separate_extension.dart b/lib/extension/separate_extension.dart
index 6af2385..0a77771 100644
--- a/lib/extension/separate_extension.dart
+++ b/lib/extension/separate_extension.dart
@@ -1,5 +1,5 @@
 import 'package:ansu_ui/ansu_ui.dart';
-extension SeparateExt<T> on List {
+extension SeparateExt<T> on List<T> {
   List<T> sep([T separate]) {
     return List.generate(this.length * 2 - 1, (index) {
       if (index.isEven)