public function isServiceLoaded(string $serviceName): bool {
        if($this->serviceExists($serviceName)) {
            if(in_array($serviceName, $this->getSelfReferenceNames()))
                return true;

            /** @var ContainerInterface $container */
            $container = $this->serviceData[$serviceName];
            return $container->isInstanceLoaded();
        }
        return false;
    }