am_event hourly not working?

Hello I have been working with Amember v 4 and now am trying to get the am_event hourly event to trigger but it seems to not be available in v4? Perhaps I am doing something wrong this is what I have
In the site.php file i have added

Am_Di::getInstance()->hook->add(Am_Event::HOURLY, 'checkOld');
function checkOld(Am_Event $event){
$file = ("test.log");
$today = mktime(0, 0, 0, date("m"), date("d"), date("Y"));
fileputcontents($file, $today);
}

When I trigger my function in other ways it works just fine so the problem is with the hook and I cant seem to figure it out. Please inform if this hook is available in v4 since the documents show it should be. Thx for any help I appreciate your time.