these 2 derivations will be built:
  /nix/store/b60dp9rk5smz4kjq7zc579qpa7bsjv9k-iets-0.1.0.drv
  /nix/store/rs4k6i6n7s2cxnmk7rzlc2bwijlki7a8-iets-langtests.drv