public static function afterPurchaseEnroll($items, $idUser)
 {
     $isAdmin = GroupController::adminCheck($idUser);
     foreach ($items as $key => $item) {
         $sale = Price::find($item->id);
         if (is_null($sale->length)) {
             $end_at = Null;
         } else {
             $date = strtotime("+" . $sale->length . " day");
             $end_at = date('Y-m-d H:i:s', $date);
         }
         if (!$isAdmin) {
             self::enroll($item->course_id, $idUser, $end_at);
         } else {
             ManagerController::addToBin($item->id, $item->qty, $idUser, $end_at);
         }
     }
 }