these 2 derivations will be built:
  /nix/store/m31vqrmr2f0yvj54fyz3jxclmn0impjd-iets-0.2.0.drv
  /nix/store/0s2jq8r1q2ragxijnqlbg6pzz3bhl386-iets-classic-2.34.9.drv