anchor.diff:  , networkd }:
   
   with import ../lib/testing-python.nix { inherit system pkgs; };
  -with pkgs.lib;
   
   let
  -  router = { config, pkgs, ... }:
  -    with pkgs.lib;
  +  router = { config, pkgs, lib, ... }:
  +    with lib;
       let
         vlanIfs = range 1 (length config.virtualisation.vlans);
       in {
  
positive.code:         '';
      };
      sit = let
        node = { address4, remote, address6 }: { pkgs, ... }: with pkgs.lib; {
          virtualisation.vlans = [ 1 ];
          networking = {
            useNetworkd = networkd;
  
negative.code:     dhcpOneIf = {
        name = "OneInterfaceDHCP";
        nodes.router = router;
        nodes.client = { pkgs, lib, ... }: with lib; {
          virtualisation.vlans = [ 1 2 ];
          networking = {
            useNetworkd = networkd;
  