{ requireFile }: requireFile
{
  name = "vasp.6.4.2.tgz";
  # nix-prefetch-url file://$(pwd)/vasp.6.4.3.tgz
  sha256 = "03j14fqjkp3w3x356d32v4vffzycqpnh7j7vmn8kyrw4fdzn615p";
  message = "Source file not found.";
}