/**
  * This function returns an instance of the Administration
  * class. It is the only way to create a new Administration, as
  * it implements the Singleton interface
  *
  * @return Administration
  */
 public static function instance()
 {
     if (!self::$_instance instanceof Administration) {
         self::$_instance = new Administration();
     }
     return self::$_instance;
 }