these 2 derivations will be built:
  /nix/store/3s9xfy8xw1vmbrfr3p1ry6sj3j3qxkn5-mardi-gras-0.34.0.drv
  /nix/store/5cyvhx151ff5cwf9kh2cdk0v6bgn82j6-check-mardi-gras.drv