/**
         * logout
         * This tells us to destroy the SSO session asn destory any cookies it created
         * This does not handle any internal or application specific session stuff
         */
        public static function logout() {

                $url = self::$_sso_login_url . '?service=' . self::$_sso_service . '&type=logout'; 

                if (!headers_sent()) {
                        header('Location: ' . $url); 
                        exit;
                } 
                else { 
                        // I should do a manual destroy if possible
                } 

        } // logout