Toner by Stamen

Toner by stamen map, is not working. As far as I can see in their website they say: As of July 31, 2023, Stamen Map Tiles are served by Stadia Maps.

So it has to be replaced by Stadia maps in order to work. Stadia requires an API.
If you get an API and enter it in the admin, then you can add the following in the theme’s functions.php:

function my_eventpost_override_toner_map($maps) {

function my_eventpost_override_toner_map($maps) {

    if (isset($maps['toner'])) {

        $maps['toner']['name'] = 'Toner by Stamen (Stadia)';
        $maps['toner']['urls'] = array(
            'https://tiles.stadiamaps.com/tiles/stamen_toner/{z}/{x}/{y}.png'
        );
        $maps['toner']['api_param'] = 'api_key';
        $maps['toner']['attribution'] = '© <a href="https://stadiamaps.com/">Stadia Maps</a> © <a href="https://stamen.com/">Stamen Design</a> © <a href="https://openstreetmap.org/">OpenStreetMap</a> contributors';
    }

    return $maps;
}
add_filter('eventpost_maps', 'my_eventpost_override_toner_map', 20);

what will get it working