Не работают только события

<?php
use Bitrix\Main\EventManager;
$eventManager = EventManager::getInstance();
$eventManager->addEventHandler("iblock", "OnBeforeIBlockElementUpdate", array("Test", "OnBeforeIBlockElementUpdate"));
$eventManager->addEventHandler("iblock", "OnAfterIBlockElementUpdate", array("Test", "OnAfterIBlockElementUpdate"));
class Test
{
    function OnBeforeIBlockElementUpdate(&$arFields){
      \Bitrix\Main\Diag\Debug::writeToFile(array('fields'=>$arFields ),"","Before.txt");
    }
    function OnAfterIBlockElementUpdate(&$arFields){
       \Bitrix\Main\Diag\Debug::writeToFile(array('fields'=>$arFields ),"","After.txt");
    }
}