private static function addObservableEvent($method, $event)
    {
        if (method_exists(get_called_class(), $method))
        {
            self::registerModelEvent($event, function($model) use ($method)
            {
                return $model->{$method}($model);
            });

            // Keep track of events
            self::$observableEvents[] = $event;
        }
    }