protected function mergeModuleConfig(string $key, array $config)
    {
        if (!empty($config)) {
            $current = $this->app['config']->get($key);
            if (is_array($current)) {
                $this->app['config']->set($key, array_merge($current, $config));
            } else {
                $this->app['config']->set($key, $config);
            }
        }
    }