anchor.diff:    src = fetchurl {
       urls = map (n: "${n}.xz") tarballUrls;
       hashOutput = false;
  -    sha256 = "a9e6c70c95f513871c5e1f4e452c04fcb3c4d8a05be651bd794cd994a52daa45";
  +    sha256 = "d9ec5ca1f47d8a85416fa26e7dc1cbf5d067640eb60e90bdc1c7e5bdc6a29984";
     };
   
     nativeBuildInputs = [
  
positive.code:   passthru = {
      srcVerification = fetchurl {
        failEarly = true;
        pgpsigUrls = map (n: "${n}.sign") tarballUrls;
        pgpDecompress = true;
        pgpKeyFingerprint = "9F6F C345 B05B E7E7 66B8  3C8F 80A7 7F60 95CD E47E";
        inherit (src) urls outputHash outputHashAlgo;
      };
    };
  
  
negative.code: }:
  
  let
    version = "4.19.0";
  
    tarballUrls = [
      "mirror://kernel/linux/utils/net/iproute2/iproute2-${version}.tar"
  