/**
  * Returns an array with nordic country codes
  *
  * @return array
  */
 static function get_nordic_countries()
 {
     global $woocommerce;
     $countries = array('NO', 'SE', 'DK', 'FI', 'IS');
     return Fraktguiden_Helper::array_filter_key($woocommerce->countries->countries, function ($k) use($countries) {
         return in_array($k, $countries);
     });
 }