protected function loadStructures($webspaceKey)
    {
        $structures = [];
        $keys = [];
        foreach ($this->structureManager->getStructures() as $page) {
            /* @var PageBridge $page */
            $template = sprintf('%s.html.twig', $page->getView());
            if ($this->templateExists($template)) {
                $keys[] = $page->getKey();
                $structures[] = $page;
            }
        }

        $this->cache->save($webspaceKey, $keys);

        return $structures;
    }