anchor.diff:    src = fetchurl {
       urls = map (n: "${n}.xz") tarballUrls;
       hashOutput = false;
  -    sha256 = "67102ac0d6795f368acc94efaca29b6626d972638790a4a0c9f89a27cd543f96";
  +    sha256 = "f3e0ec4864b7b89db1a6a36fa48bf8a9217117714a04b13c84d0fea1eac154b2";
     };
   
     nativeBuildInputs = [
  
positive.code: }:
  
  let
    version = "4.15.1";
  
    tarballUrls = [
      "mirror://kernel/linux/kernel/people/kdave/btrfs-progs/btrfs-progs-v${version}.tar"
  
negative.code:     zstd
    ];
  
    configureFlags = [
      "--disable-python"
    ];
  
    passthru = {
      srcVerification = fetchurl rec {
  