these 2 derivations will be built:
  /nix/store/8af3ycn9wpg0h1nn8rxw4imvvijspjyv-iets-0.2.0.drv
  /nix/store/8ing70kl56mj8zshcq2yci04awi3japi-iets-classic-2.34.9.drv