public function load_choices() {
        global $CFG, $DB;
        if (during_initial_install()) {
            return false;
        }
        if (is_array($this->choices)) {
            return true;
        }
        if ($roles = get_all_roles()) {
            $this->choices = role_fix_names($roles, null, ROLENAME_ORIGINAL, true);
            return true;
        } else {
            return false;
        }
    }