anchor.diff:    src = fetchurl {
       urls = tarballUrls version;
       hashOutput = false;
  -    sha256 = "c8a18bc6259da0c3eefefb018f8aa298fddc6f86c6fc0f0dec73270896ab512f";
  +    sha256 = "7cd8cc2e35b1aaede6084ea57cc9447752f498daaea854100a4bad567614977d";
     };
   
     buildInputs = [
  
positive.code: }:
  
  let
    version = "1.16";
  
    tarballUrls = version: [
      "mirror://gnu/gdbm/gdbm-${version}.tar.gz"
  
negative.code:   passthru = {
      srcVerification = fetchurl rec {
        failEarly = true;
        urls = tarballUrls "1.17";
        pgpsigUrls = map (n: "${n}.sig") urls;
        pgpKeyFingerprint = "325F 650C 4C2B 6AD5 8807  327A 3602 B07F 55D0 C732";
        inherit (src) outputHashAlgo;
        outputHash = "7cd8cc2e35b1aaede6084ea57cc9447752f498daaea854100a4bad567614977d";
      };
    };
  
  