public static function getInstance($name = null)
 {
     // Get the late-static-binding version of __CLASS__
     $class = get_called_class();
     // Allow passing in a name to get multiple instances
     // If you do not pass a name, it functions as a singleton
     $name = !is_null($name) ?: $class;
     if (!Registry::contains($name)) {
         $instance = new $class();
         Registry::add($instance, $name);
     }
     return Registry::get($name);
 }