these 2 derivations will be built:
  /nix/store/889f9nj65p777xd7d5hpzjfiyc5j3d4d-iets-0.1.0.drv
  /nix/store/nm234ax9a1hw1sfl2iaxrxjhgwqhj3dn-iets-langtests.drv