these 3 derivations will be built:
  /nix/store/f2gf4pzf0wygcv63fp8pssydkbix2iwa-cpa-usage-keeper-frontend-2.0.0.drv
  /nix/store/frxjbsib4r4xdmxq8ji7rd63bj5chnwx-cpa-usage-keeper-2.0.0.drv
  /nix/store/cxn8sy733mmplrjsf2w34zgpfs7kdwkn-check-cpa-usage-keeper.drv