these 2 derivations will be built:
  /nix/store/h8d6mg8lwl7bw28yzq24l2g46lnca8s9-iets-0.1.0.drv
  /nix/store/fyfy7rbn5j3iqm3av8rai7i3wx8jlzix-iets-langtests.drv