these 2 derivations will be built:
  /nix/store/vsq24zllgaasndp7g0sdybvnpfjqxzd1-mardi-gras-0.32.1.drv
  /nix/store/z9zaak6gbbpzw30zd2gmvlf5h1n066wy-check-mardi-gras.drv