Catchable fatal error: Argument 1 passed to AppBundle\Controller\Course\CourseSetController::getTagIdsByCourseSet() must be of the type array, null given, called in /var/www/xue.yikeos.com/src/AppBundle/Controller/Course/CourseSetController.php on line 115 and defined in /var/www/xue.yikeos.com/src/AppBundle/Controller/Course/CourseSetController.php on line 161