these 3 derivations will be built:
  /nix/store/3y7kbwx962hjl1vcn8xmj2awh5n5w93s-cpa-usage-keeper-frontend-1.15.9.drv
  /nix/store/4gqlg11lsn7nlilckylg76szby2rkpga-cpa-usage-keeper-1.15.9.drv
  /nix/store/vjnkxn0iq1hb542iyj7xbbvild87ady1-check-cpa-usage-keeper.drv