these 2 derivations will be built:
  /nix/store/vaxkxvvi05az6y8rlvs5f4ysh8ybg8nq-iets-0.1.0.drv
  /nix/store/1jl59qj3d6pv9sdg90kbvr2i2z4pwi2b-iets-langtests.drv