public function getMessage($id = null)
    {
        if (!is_null($id)) {
            return array_key_exists($id, $this->messages) ? $this->messages[$id] : null;
        } elseif (count($this->messages)>0) {
            return current($this->messages);
        } else {
            $message_class = $this->getDefault('messager');
            if (class_exists($message_class)) {
                $this->addMessage(new $message_class);
                return current($this->messages);
            } else {
                throw new \Exception(
                    sprintf('Default message class "%s" not found!', $message_class)
                );
            }
        }
    }