these 2 derivations will be built:
  /nix/store/mglw48xhhp7hadsdxk5wwcq92xr394x7-iets-0.2.0.drv
  /nix/store/v30k7i5mja7cib4j8xw3hcq75fip3qlj-iets-classic-2.34.9.drv