these 3 derivations will be built:
  /nix/store/678h2rfglxzysd13al7dmy7x15wzz5yi-cpa-usage-keeper-frontend-2.1.0.drv
  /nix/store/rrrvdnyv25s0ylh4i5b0li8iyf4mslyb-cpa-usage-keeper-2.1.0.drv
  /nix/store/9p60hnb25gskrv847i7jpmnn2zvvchrj-check-cpa-usage-keeper.drv