如何在Google+中获取我圈子里的朋友列表

我想得到我圈子里的朋友列表（Google+）。我没有得到那个名单；我的代码如下：

    require_once('assets/google/Google_Client.php');
    require_once('assets/google/contrib/Google_Oauth2Service.php');
    require_once('assets/google/contrib/Google_PlusService.php');
    $gClient = new Google_Client();
    $gClient->setApplicationName('Login to Google');
    $gClient->setClientId(GOOGLE_CLIENT_ID);
    $gClient->setClientSecret(GOOGLE_CLIENT_SECRET);
    $gClient->setRedirectUri($google_redirect_url);
    $gClient->setDeveloperKey(GOOGLE_DEVELOPER_KEY);
    $gClient->setScopes($scope);
    $google_oauthV2 = new Google_Oauth2Service($gClient);
    $google_plus = new Google_PlusService($gClient);
    if (isset($_GET['code'])){ 
        $gClient->authenticate($_GET['code']);
        $_SESSION['token'] = $gClient->getAccessToken();
        header('Location: ' .filter_var($google_redirect_url,FILTER_SANITIZE_URL));
        return;
    }
    $user = $google_oauthV2->userinfo->get();

我通过调用上述函数来获取我的详细信息

$peoples = $google_plus->people->listPeople('me','visible');

当我使用上面的调用来获取人员列表时，我得到的权限不足（403）。有人能帮我解决这个问题吗？