these 2 derivations will be built:
  /nix/store/cjk3rkzxfq5wnnkan7k61vdxlp8a2fvh-iets-0.1.0.drv
  /nix/store/c18jscnf32jnfl6ag4bqcb866dqq94rx-iets-langtests.drv