private function loadConfig(string $itemType): Configuration
    {
        $service = 'netgen_content_browser.config.' . $itemType;

        if (!$this->container->has($service)) {
            throw new InvalidArgumentException(
                sprintf(
                    'Configuration for "%s" item type does not exist.',
                    $itemType
                )
            );
        }

        $config = $this->container->get($service);
        if (!$config instanceof Configuration) {
            throw new InvalidArgumentException(
                sprintf(
                    'Configuration for "%s" item type is invalid.',
                    $itemType
                )
            );
        }

        return $config;
    }