protected final function getReflection(string $className): ReflectionClass
   {
       try {
           $reflexion = new ReflectionClass($className);
       } catch (ReflectionException $e) {
           throw new NotFoundException(
               "Can't get reflection for " . $className . ": not found");
       }
       if (!$reflexion->isInstantiable()) {
           throw new ContainerException(
               "Can't get reflection for " . $className . ": not instanciable");
       }
       return $reflexion;
   }