/**
  * Use MAXMIND GeoLite database to geolocation the user.
  * @param  string $ip_address
  * @return string
  */
 private static function geolocate_via_db($ip_address)
 {
     if (!class_exists('WC_Geo_IP')) {
         include_once 'class-wc-geo-ip.php';
     }
     $gi = new WC_Geo_IP();
     if (self::is_IPv6($ip_address)) {
         $database = self::get_local_database_path('v6');
         $gi->geoip_open($database, 0);
         $country_code = $gi->geoip_country_code_by_addr_v6($ip_address);
     } else {
         $database = self::get_local_database_path();
         $gi->geoip_open($database, 0);
         $country_code = $gi->geoip_country_code_by_addr($ip_address);
     }
     $gi->geoip_close();
     return sanitize_text_field(strtoupper($country_code));
 }