Minor thing: I have goose bumps when I see $GLOBALS in PHP :smile:

I wonder if  something like this would work the same:

```php
global $wgCityId, $$cv_name;

if($city_id == $wgCityId){
    return isset($$cv_name) ? $$cv_name : null;
}
```

If that works I'd personally prefer to rely on a PHP language feature than a PHP functionality (which can be disabled via config IIRC).