these 2 derivations will be built:
  /nix/store/lcsmly69f3s0skmyj8rjhwhhvqrh3ws9-iets-0.1.0.drv
  /nix/store/87gcfxbg4wsmkcxpi0v8p9ywn8pzv60a-iets-langtests.drv