remove some cities from the list

How I remove some cities from the list? I found the solution code like this:

add_filter( 'csz_cities', 'csz_remove_cities' );
function csz_remove_cities( $cities ) {
         $country_code="EE"; 
         $unnecessary_cities = [ 'EE784', 'EE296', 'EE446' ]; 
         foreach ( $unnecessary_cities as $city ) { 
                  if ( isset( $cities[ $country_code ][ $city ] ) ) {
                      unset( $cities[ $country_code ][ $city ] ); 
                  } 
         } 
         return $cities;
 }

In this code, the country code ‘EE’ is for Estonia and ‘EE784’, ‘EE296’, ‘EE446’ are the cities code of Estonia. But I can’t test it because I don’t know how to check the country code.

I would know how can I find the country code for Myanmar and cities code?