anchor.diff:        serviceConfig = {
           Type = "dbus";
           BusName = "net.connman.vpn";
  -        ExecStart = "${pkgs.connman}/sbin/connman-vpnd -n";
  +        ExecStart = "${cfg.package}/sbin/connman-vpnd -n";
           StandardOutput = "null";
         };
       };
  
positive.code:       serviceConfig = {
          Name = "net.connman.vpn";
          before = [ "connman" ];
          ExecStart = "${pkgs.connman}/sbin/connman-vpnd -n";
          User = "root";
          SystemdService = "connman-vpn.service";
        };
  
negative.code:       message = "You can not use services.connman with networking.networkmanager";
      }];
  
      environment.systemPackages = [ cfg.package ];
  
      systemd.services.connman = {
        description = "Connection service";
  