let
  pkgs = import (fetchGit {
    name = "nixos-unstable-2020-02-12";
    url = https://github.com/nixos/nixpkgs-channels/;
    rev = "a21c2fa3ea2b88e698db6fc151d9c7259ae14d96";
  });

  cfg = {
    overlays = [
      (import ./provision.nix)
    ];
  };

in pkgs cfg