CI-Neo4jPHP，从节点获取标签

Question

以下脚本在CI和Neo4jPHP环境中编写。

    $client = new Everyman\Neo4j\Client("localhost", 7474);
    $client->getTransport()->setAuth("admin","password");

    $all_labels = $client->getLabels();
    foreach ($all_labels as $key=>$a_label)
    {
        echo $key.": ".$a_label->getName()."\n";
    }

预期的标签清单， 但我没有得到任何东西。