public function page_after_submit() {
        global $CFG;
        require_once($CFG->libdir . '/filelib.php');

        $pageaftersubmit = $this->get_feedback()->page_after_submit;
        if (empty($pageaftersubmit)) {
            return null;
        }
        $pageaftersubmitformat = $this->get_feedback()->page_after_submitformat;

        $context = context_module::instance($this->get_cm()->id);
        $output = file_rewrite_pluginfile_urls($pageaftersubmit,
                'pluginfile.php', $context->id, 'mod_feedback', 'page_after_submit', 0);

        return format_text($output, $pageaftersubmitformat, array('overflowdiv' => true));
    }