these 2 derivations will be built:
  /nix/store/8n3fw269yizq5alkr5jkjcac0c9z59nb-iets-0.1.0.drv
  /nix/store/kgfpqjgwwjwq3h9qc5ykjnnr5a5x8dd5-iets-langtests.drv