diff --git a/lib/flavor_helper.dart b/lib/flavor_helper.dart
index ed3705a..ad5a78d 100644
--- a/lib/flavor_helper.dart
+++ b/lib/flavor_helper.dart
@@ -152,7 +152,7 @@ class _FlavorHelper {
   }
 }
 
-extension StringExtension on String {
+extension _StringExtension on String {
   String capitalize() {
     return "${this[0].toUpperCase()}${substring(1).toLowerCase()}";
   }