anchor.diff:      # Add ntpctl to the environment for status checking
       environment.systemPackages = [ package ];
   
  +    environment.etc."ntpd.conf".text = configFile;
  +
       users.extraUsers = singleton {
         name = "ntp";
         uid = config.ids.uids.ntp;
  
positive.code:       type = with types; lines;
        default = "";
        example = ''
          listen on 127.0.0.1 
          listen on ::1 
        '';
        description = ''
          Additional text appended to <filename>openntpd.conf</filename>.
  
negative.code: 
    package = pkgs.openntpd_nixos;
  
    configFile = ''
      ${concatStringsSep "\n" (map (s: "server ${s}") cfg.servers)}
      ${cfg.extraConfig}
    '';
  