these 2 derivations will be built:
  /nix/store/cjk3rkzxfq5wnnkan7k61vdxlp8a2fvh-iets-0.1.0.drv
  /nix/store/s9rzg9wqx2dccfx6l1ii6x7inv9yn8f3-iets-partest.drv