diff --git a/src/CoreBundle/DependencyInjection/ChamiloCoreExtension.php b/src/CoreBundle/DependencyInjection/ChamiloCoreExtension.php
index d6ade2aee2..c16ce06ec5 100644
--- a/src/CoreBundle/DependencyInjection/ChamiloCoreExtension.php
+++ b/src/CoreBundle/DependencyInjection/ChamiloCoreExtension.php
@@ -36,7 +36,7 @@ class ChamiloCoreExtension extends Extension
     /**
      * @return string
      */
-    public function getAlias()
+    public function getAlias(): string
     {
         return 'chamilo_core';
     }