Habari\Session::error PHP Метод

Store an error message in the user's session

public static error ( string $error, string $key = null )
$error	string	The error message
$key	string	An optional id that would guarantee a single unique message for this key

    public static function error($error, $key = null)
    {
        self::add_to_set('errors', $error, $key);
    }

Session