public function mapLazyService(string $name, $class = null)
    {
        if (isset($this->services[$name]) && ! $this->allowOverride) {
            throw ContainerModificationsNotAllowedException::fromExistingService($name);
        }
        $this->lazyServicesClassMap[$name] = $class ?? $name;
        $this->lazyServicesDelegator = null;
    }