public function message($ruleOrMessage, $message = null)
    {
        if (1 === func_num_args()) {
            $rule = $this->lastRule;
            $message = $ruleOrMessage;
        } else {
            $rule = $ruleOrMessage;
        }

        $this->options['messages'][$this->lastKey][$rule] = $message;

        return $this;
    }