protected function extractItems(\DOMDocument $dom, \Generator $parsers)
    {
        $items     = [];
        $extractor = new ExtractorService();
        foreach ($parsers as $parser) {
            $results = $extractor->extract($dom, $parser);
            $items   = array_merge($items, ItemFactory::createFromApplicationItems($results->getItems()));
        }

        return $items;
    }