如何阅读这个facebook带领示例代码

Question

我使用facebook成功登录但我想运行此示例代码，我可以在哪里放置此示例来测试它

use FacebookAds\Api;
use FacebookAds\Http\RequestInterface;

$params = array(
  'user_id' => <USER_ID>,
);

$response = Api::instance()->call(
  '/me/leadgen_whitelisted_users',
  RequestInterface::METHOD_POST,
  $params);

我在登录后把它放入，然后我收到此错误Call to a member function call() on a non-object