import (
  let
    lock = builtins.fromJSON (builtins.readFile ./flake.lock);
  in fetchTarball {
    url = "https://api.github.com/repos/NixOS/nixpkgs/tarball/${lock.nodes.nixpkgs.locked.rev}";
    sha256 = lock.nodes.nixpkgs.locked.narHash;
  }
)