public function set($key, $value)
    {
        if (0 == \strlen($key)) {
            throw new CasbinException('key is empty');
        }

        $section = '';

        $keys = explode('::', strtolower($key));
        if (\count($keys) >= 2) {
            $section = $keys[0];
            $option = $keys[1];
        } else {
            $option = $keys[0];
        }
        $this->addConfig($section, $option, $value);
    }