public function getPlaylists(): array
    {
        if (is_array($this->playlists)) {
            return $this->playlists;
        }

        $controller = $this->getController();
        $data = $controller->soap("ContentDirectory", "Browse", [
            "ObjectID"          =>  "SQ:",
            "BrowseFlag"        =>  "BrowseDirectChildren",
            "Filter"            =>  "",
            "StartingIndex"     =>  0,
            "RequestedCount"    =>  100,
            "SortCriteria"      =>  "",
        ]);
        $parser = new XmlParser($data["Result"]);

        $playlists = [];
        foreach ($parser->getTags("container") as $container) {
            $playlists[] = new Playlist($container, $controller);
        }

        return $this->playlists = $playlists;
    }