{ pkgs ? import <nixpkgs> { } }:
let
  nixpkgs = fetchTarball
  { url = "https://github.com/NixOS/nixpkgs-channels/archive/4557b9f1f50aa813ae673fe6fcd30ca872968947.tar.gz";
    sha256 = "0cam48cn042axcik9vqxsqjc2hwyb2grjbjxacsn4w0y1zk6k6l2";
  };
  args =
  { overlays = [ (import ./overlays.nix) ];
  };
in
pkgs.callPackage nixpkgs args