public function createSubsidiary($name, $config)
    {
        if (!is_string($name) || empty($name)) {
            return null;
        }
        $className = '';
        if (class_exists($name)) {
            $className = $name;
        } elseif (array_key_exists($name, $this->subsidiaryMap)) {
            $className = $this->getSubsidiaryClass($name);
        } else {
            return null;
        }
        return $this->create($className, $config);
    }