args:
import (builtins.fetchTarball {
  name   = "nixpkgs-unstable";
  url    = "https://github.com/NixOS/nixpkgs-channels/archive/91d5b3f07d27622ff620ff31fa5edce15a5822fa.tar.gz";
  sha256 = "09vlhjbkjivv9aiklhwq9wpzn954pcyp3fhrwslm28ip4iar9b55";
}) args // { config.allowUnfree = true; }