Integration with Events-Manager

Hi,
in the following post
https://www.ads-software.com/support/topic/events-manager-integration-question/

It is explaining how to add the Event Id to Mailchimp following a registration to an event.

I have copied the proposed action to my function.php but that did not work.
Has this been tested… am I missing something.

Here is my liitle function:

add_filter(‘mc4wp_integration_events-manager_data’, function( $data ) {
$data[‘EVENT_ID’] = $_POST[’em_id’];
return $data;
});

The page I need help with: [log in to see the link]