$httpClient =
Zend_Gdata_ClientLogin::getHttpClient(
$username = '****@gmail.com',
$password = '*****',
$service = 'youtube',
$client = null,
$source = 'testphp',
$loginToken = null,
$loginCaptcha = null,
$authenticationURL);
我从 code.google.com 获得了上述代码。我想知道authenticationURL
应该是什么。我是新手,帮帮我