protected function view_return_links() {
        $returnaction = optional_param('returnaction', '', PARAM_ALPHA);
        $returnparams = optional_param('returnparams', '', PARAM_TEXT);

        $params = array();
        $returnparams = str_replace('&amp;', '&', $returnparams);
        parse_str($returnparams, $params);
        $newparams = array('id' => $this->get_course_module()->id, 'action' => $returnaction);
        $params = array_merge($newparams, $params);

        $url = new moodle_url('/mod/assign/view.php', $params);
        return $this->get_renderer()->single_button($url, get_string('back'), 'get');
    }