diff --git a/Models/Calendar.php b/Models/Calendar.php
index 09dd935..5fee4fe 100644
--- a/Models/Calendar.php
+++ b/Models/Calendar.php
@@ -149,9 +149,9 @@ class Calendar
     {
         $this->events[] = $event;
 
-        end($this->events);
+        \end($this->events);
         $key = \key($this->events);
-        reset($this->events);
+        \reset($this->events);
 
         return $key;
     }