VK PHP SDK | Не работают методы

<?php 
require_once 'vendor/autoload.php'; 
$vk = new VK\Client\VKApiClient('5.92'); 
$access_token = 'я скрыл'; 
class ServerHandler extends VK\CallbackApi\Server\VKCallbackApiServerHandler { 
    const SECRET = 'secret'; 
    const GROUP_ID = 123123; 
    const CONFIRMATION_TOKEN = 'ewewe'; 
 
    function confirmation(int $group_id, ?string $secret) { 
        if ($secret === static::SECRET && $group_id === static::GROUP_ID) { 
            echo static::CONFIRMATION_TOKEN; 
        } 
    } 
 
    public function messageNew(int $group_id, ?string $secret, array $object) { 
      $response = $vk->users()->get($access_token, array( 
        'user_ids' => array(1, 210700286), 
        'fields' => array('city', 'photo'), 
    )); 
        echo 'ok'; 
    } 
} 
 
$handler = new ServerHandler(); 
$data = json_decode(file_get_contents('php://input')); 
$handler->parse($data); 
?>

<b>Fatal error</b>:  Uncaught Error: Call to a member function users() on null in /home/host1752721/serv/htdocs/www/core.php:18 
Stack trace: 
#0 /home/host1752721/serv/htdocs/www/src/VK/CallbackApi/VKCallbackApiHandler.php(312): ServerHandler-&gt;messageNew(178736000, 'pass', Array) 
#1 /home/host1752721/serv/htdocs/www/src/VK/CallbackApi/Server/VKCallbackApiServerHandler.php(28): VK\CallbackApi\VKCallbackApiHandler-&gt;parseObject(178736000, '161491amin', 'message_new', Array) 
#2 /home/host1752721/serv/htdocs/www/core.php(28): VK\CallbackApi\Server\VKCallbackApiServerHandler-&gt;parse(Object(stdClass)) 
#3 {main} 
  thrown in <b>/home/host1752721/serv/htdocs/www/core.php</b> on line <b>18</b><br />