these 2 derivations will be built:
  /nix/store/2hrqik3prc3aqyvkiknkkvx4kyjixc7q-iets-0.2.0.drv
  /nix/store/4xymgmviwbv5x05sff9pwlilv1q0szwz-iets-classic-2.34.9.drv