anchor.diff:  
     src = fetchurl {
       urls = tarballUrls version;
  -    sha256 = "0d8fed192563c324bb5ace3c068f06558a5569a6e8eb47eee1cd79ada3b1124f";
  +    hashOutput = false;
  +    sha256 = "b89d3824a802af29605b9cbec48f4ce8a80f90ee933a3192f3ac252db121c9ea";
     };
   
     buildInputs = [
  
positive.code:   passthru = {
      srcVerification = fetchurl rec {
        failEarly = true;
        urls = tarballUrls "0.23.5";
        pgpsigUrls = map (n: "${n}.sig") urls;
        pgpKeyFingerprints = [
          "AED6 E2A1 85EE B379 F174  76D2 E012 D07A D0E3 CC30"
          "4622 25C3 B46F 3487 9FC8  496C D605 848E D7E6 9871"
        ];
        inherit (src) outputHashAlgo;
        outputHash = "0d8fed192563c324bb5ace3c068f06558a5569a6e8eb47eee1cd79ada3b1124f";
      };
    };
  
  
negative.code: }:
  
  let
    version = "0.23.6";
  
    tarballUrls = version: [
      "https://github.com/p11-glue/p11-kit/releases/download/${version}/p11-kit-${version}.tar.gz"
  