these 2 derivations will be built:
  /nix/store/j7pzmk6n6wzdnlc3g5xhwzlgprj3j463-iets-0.1.0.drv
  /nix/store/sw8w2grjv68d3978hfz8j570yhsj4f7c-iets-langtests.drv