these 2 derivations will be built:
  /nix/store/2f10g0zjm0ydd0w21g6g3wfnd8c5bp0n-iets-0.1.0.drv
  /nix/store/31zx58s27z8xp4k2kxa4m9hydikd3m3m-iets-langtests.drv