protected function registerServices()
    {
        foreach (self::$diMap as $serviceKey => $serviceClass) {
            if (\is_int($serviceKey)) {
                $this->register(new $serviceClass);
            } else {
                $this[$serviceKey] = function ($c) use ($serviceClass) {
                    return new $serviceClass($c);
                };
            }
        }
    }