too long

I am exploring the Facebook API for a couple of days now, because I am trying to get leads from my Facebook page using Webhooks with Lead Ads.

After reading a bunch of articles and Facebook documentation I noticed that for a lot functions in the documentation you see a $session variable defined (for example here and here).

Because I want to get the leads from my Facebook page I started following this article, which explains how to get real time lead updates from Facebook.

The article starts with setting up a request for receiving the app subscriptions for your Facebook page. But I directly came into trouble with creating the session, because it looks like the FacebookSession class does not exists in the current Facebook SDK anymore.

How do I need to setup this session? Because I can not find anywhere in the SDK files the FacebookSession class, so I think in the mean time this is changed.

require_once __DIR__ . '/facebook-sdk-v5/autoload.php';

use Facebook\FacebookSession;
use Facebook\FacebookRequest;

// I cannot find this class anywhere
$session = new FacebookSession('<APP_ACCESS_TOKEN>');

$request = new FacebookRequest(
  $session,
  'POST',
  '/<APP_ID>/subscriptions',
  array(
    'object' => 'page',
    'callback_url' => '<YOUR_CALLBACK_URL>',
    'fields' => 'conversations',
    'verify_token' => '<YOUR_VERIFY_TOKEN>',
  )
);
$response = $request->execute();

I get an 500 server error with the following message:

Fatal error: Class 'Facebook\FacebookSession' not found in ...