these 2 derivations will be built:
  /nix/store/7g07vkkhdf84zz13jxnlh2iq63bdyhl1-iets-0.1.0.drv
  /nix/store/ifdcvg6z0j1w0sw1m49kq5s47lsq59p0-iets-langtests.drv