these 2 derivations will be built:
  /nix/store/c1d9lvsihxqx6fvbq1rjhryi82s8cy0l-iets-0.1.0.drv
  /nix/store/f8bsldf9frkcjrvbvjlr2smn7gjs2ggp-iets-langtests.drv