private function addArtifactToUsedGenerators($allGenerators, $feature, $func) {
        $artifact = $this->productLine->getArtifact($feature);
        foreach ($artifact->getGenerators() as $key => $cfg) {
            if (!array_key_exists($key, $allGenerators))
                throw new ProductException("\"$key\" is not a valid generator");
            call_user_func(array($allGenerators[$key], $func), $artifact);
        }
    }