如何检索Google Calendar Resources PHP API客户端？

 $client = new Google_Client();

 $client->setApplicationName('Google Calendar API PHP');

 $client->setScopes(Google_Service_Calendar::CALENDAR_READONLY);

 $client->setAuthConfig('path/to/client_secret.json');

 $client->setAccessType('offline');

 $tokenPath = 'path/to/token.json';

 if (file_exists($tokenPath)) {

     $accessToken = json_decode(file_get_contents($tokenPath), true);

     $client->setAccessToken($accessToken);

 } else {

     $authUrl = $client->createAuthUrl();

     printf("Open the following link in your browser:\n%s\n", $authUrl);

     print 'Enter verification code: ';

     $authCode = trim(fgets(STDIN));

     $accessToken = $client->fetchAccessTokenWithAuthCode($authCode);

     if (!file_exists(dirname($tokenPath))) {

         mkdir(dirname($tokenPath), 0700, true);

     }

     file_put_contents($tokenPath, json_encode($accessToken));

     printf("Token stored in %s\n", $tokenPath);

 }

 $service = new Google_Service_Calendar($client);

 $calendarList = $service->calendarList->listCalendarList();

 foreach ($calendarList->getItems() as $calendarListEntry) {

     echo $calendarListEntry->getSummary() . "\n";

 }

 ```