anchor.diff:  
       environment.systemPackages =  [ pkgs.hostapd ];
   
  -    services.udev.packages = [ pkgs.crda ];
  +    services.udev.packages = optional (cfg.countryCode != null) [ pkgs.crda ];
   
       systemd.services.hostapd =
         { description = "hostapd wireless AP";
  
positive.code:         '';
        };
  
        extraConfig = mkOption {
          default = "";
          example = ''
  
negative.code:     ssid=${cfg.ssid}
      hw_mode=${cfg.hwMode}
      channel=${toString cfg.channel}
      ${optionalString (cfg.countryCode != null) ''country_code=${cfg.countryCode}''}
  
      # logging (debug level)
      logger_syslog=-1
  