these 2 derivations will be built:
  /nix/store/55vcpfz1im7kpswgb3mnn3r9wlzlgh7q-iets-0.1.0.drv
  /nix/store/z4fhsa2hjy2yxragrxd2ldvf8niricl8-iets-diff-e2e.drv