PHP GoogleCalendarAPI FreeBusy

Question

我在Laravel中遇到错误：

Class 'Google_FreeBusyRequest' not found

但是我在开始控制器上添加了代码：

use Google_FreeBusyRequest;
use Google_FreeBusyRequestItem;

两个班都有错误。

在这堂课之前全部工作：

    $client = new Google_Client();
    $client->setAuthConfig(__DIR__.'client_secret.json');
    $client->addScope(Google_Service_Calendar::CALENDAR);
    $client->setRedirectUri('http://' . $_SERVER['HTTP_HOST'] . '/oauth2calendar');
    $client->setAccessType("offline");
    $client->setAccessToken($access);

    $calendar_service = new Google_Service_Calendar($client);

    $freebusy_req = new Google_FreeBusyRequest();//crash
    $freebusy_req->setTimeMin(date(DateTime::ATOM, strtotime("2017-02-21 08:00:00")));
    $freebusy_req->setTimeMax(date(DateTime::ATOM, strtotime("2017-02-21 23:00:00")));
    $item = new Google_FreeBusyRequestItem();//crash
    $item->setId('primary');
    $freebusy_req->setItems(array($item));
    $query = $calendar_service->freebusy->query($freebusy_req);


    dd($query);

为什么？