these 2 derivations will be built:
  /nix/store/1bdwwmxblmvhyd6md7slmwh902pp9hha-iets-0.1.0.drv
  /nix/store/6xb63w5a1jljp70141am89xp341cr5gp-iets-langtests.drv
building '/nix/store/6xb63w5a1jljp70141am89xp341cr5gp-iets-langtests.drv'