let
  nixpkgs = builtins.fetchTarball {
     name = "nixos-20.03";
     url = "https://github.com/nixos/nixpkgs/archive/a84b797b28eb104db758b5cb2b61ba8face6744b.tar.gz";
     sha256 = "0f3s0m3bdd857s7zrgghl6vmj3hjqfaqcnd7sg33fzwakagwy0fp";
  };
  nixos = import "${nixpkgs}/nixos" {
    configuration = {
      imports = [
        ./configuration.nix
      ];
    };
  };
in
  nixos.system