public static function isAuthMethod (string $method)
    {
        $auth = self::$_authMethods;

        if (empty($method)) :
            throw new CondorcetException (8);
        endif;

        if ( isset($auth[$method]) ) :
            return $method;
        else : // Alias
            foreach ($auth as $class => &$alias) :
                foreach ($alias as &$entry) :
                    if ( strcasecmp($method,$entry) === 0 ) :
                        return $class;
                    endif;
                endforeach;
            endforeach;
        endif;

        return false;
    }