these 2 derivations will be built:
  /nix/store/qqzjl3r43srx1vc3vz6pr1qyjsj9hv5f-iets-0.1.0.drv
  /nix/store/br2889xc3cpg4z4kqinbb2s0vzim93n1-iets-langtests.drv