public function index()
    {
        if ($cachedView = $this->getCachedView()) {
            return response()->make($cachedView, 200, ['Content-type' => 'text/xml']);
        }

        $sitemapIndex = response()->view('sitemap::sitemaps', ['__sitemaps' => $this->getSitemaps()], 200, ['Content-type' => 'text/xml']);

        $this->saveCachedView($sitemapIndex);

        return $sitemapIndex;
    }