private function getStageInstance(string $stageClass): StageInterface
    {
        if (!class_exists($stageClass)) {
            throw new RuntimeException('Error: Could not find requested stage class.');
        }
        if (in_array("Zikula\\Component\\Wizard\\InjectContainerInterface", class_implements($stageClass), true)) {
            return new $stageClass($this->container);
        }

        return new $stageClass();
    }