these 2 derivations will be built:
  /nix/store/gazgj7gwfc1kjzkwsrkhvqwh7kf9g8wc-iets-0.1.0.drv
  /nix/store/j61w3k870l7hc8cn9h7z3j5h3xnp752y-iets-langtests.drv