these 2 derivations will be built:
  /nix/store/c4s6nd1bdm45h66chzsh7k8llb56rph4-iets-0.1.0.drv
  /nix/store/8304lmxw0mzrrb3557wjy2xblldv4jw9-iets-langtests.drv
building '/nix/store/8304lmxw0mzrrb3557wjy2xblldv4jw9-iets-langtests.drv'