import (fetchTarball {
  url = "https://github.com/NixOS/nixpkgs/archive/17812e653d89c46d68b7b10e290b1c16758f4e47.tar.gz";
  sha256 = "1zcb70dyfqc8l2ywpbvxmpfshapdi0g365m3rhmwpagqg47pnyxs";
})