anchor.diff:        connectionURI = mkOption {
           type = types.str;
           default =
  -          if cfg.backend == "qemu" then "qemu:///system"
  +          if backend == "qemu" then "qemu:///system"
             else "lxc:///";
         };
   
  
positive.code:       };
  
        nixos.modules = singleton {
          services.nscd.enable = cfg.backend != "lxc";
          users.extraUsers.root.password = "root";
          services.journald.extraConfig = ''
            Storage=volatile
  
negative.code:       _module.args = { inherit pkgs; };
  
        libvirt.domain = {
          inherit backend;
          lxc = mkIf (backend == "lxc") {
            mappedUid = "@uid@";
            mappedGid = "@gid@";
            rootPath = "/@mnt@/root-${name}";
  