protected function show_hide_tour($tourid, $visibility) {
        global $DB;

        require_sesskey();

        $tour = $DB->get_record('tool_usertours_tours', array('id' => $tourid));
        $tour->enabled = $visibility;
        $DB->update_record('tool_usertours_tours', $tour);

        redirect(helper::get_list_tour_link());
    }