How to show country flag by abbr?

Hello,
In my Laravel 8 app I need to show country flag and I installed package
antonioribeiro/countries-laravel

But I did not fin if it supports abbreviation(like ‘AF’,'FR') ?

I trierd to make like : 
            $nextFlag = Countries::where('abbreviation', 'AF');
and several options like 'abbreviation', but in all cases I ghot empty collection...

Which way is valid ?

Thanks!