public function level($level)
    {
        if (empty($level)) {
            $level = [];
        } elseif (is_string($level)) {
            $level = explode(',', str_replace(' ', '', $level));
        } else {
            $level = is_array($level) ? $level : func_get_args();
        }

        $this->setLevel($level);

        return $this;
    }