protected function add_plugin_submission_elements($submission,
                                                    MoodleQuickForm $mform,
                                                    stdClass $data,
                                                    $userid) {
        foreach ($this->submissionplugins as $plugin) {
            if ($plugin->is_enabled() && $plugin->is_visible() && $plugin->allow_submissions()) {
                $plugin->get_form_elements_for_user($submission, $mform, $data, $userid);
            }
        }
    }