diff --git a/app/controllers/calendar/calendar.php b/app/controllers/calendar/calendar.php
index 27048fb3c98a7825cbe79e5391410ced5f51084f..0c24a8025d099bda2add252f7f9d7eec41a613c8 100644
--- a/app/controllers/calendar/calendar.php
+++ b/app/controllers/calendar/calendar.php
@@ -12,8 +12,12 @@ class Calendar_CalendarController extends AuthenticatedController
     }
 
 
-    protected function buildSidebar($schedule = false, $user_id = '', $group_id = '')
-    {
+    protected function buildSidebar(
+        bool $schedule = false,
+        string $user_id = '',
+        string $group_id = ''
+    ) {
+
         $sidebar = Sidebar::get();
 
         $actions = new ActionsWidget();