anchor.diff:  
     config = mkIf cfg.enable {
   
  -    environment.systemPackages = [ pkgs.unbound ];
  +    environment.systemPackages = [ cfg.package ];
   
       users.users.unbound = {
         description = "unbound daemon user";
  
positive.code:       '';
  
        serviceConfig = {
          ExecStart = "${pkgs.unbound}/bin/unbound -d -c ${stateDir}/unbound.conf";
          ExecStopPost="${pkgs.utillinux}/bin/umount ${stateDir}/dev/random";
  
          ProtectSystem = true;
  
negative.code: 
        enable = mkEnableOption "Unbound domain name server";
  
        package = mkOption {
          type = types.package;
          default = pkgs.unbound;
          defaultText = "pkgs.unbound";
          description = "The unbound package to use";
        };
  
        allowedAccess = mkOption {
          default = [ "127.0.0.0/24" ];
          type = types.listOf types.str;
  