anchor.diff:    passthru = {
       srcVerification = fetchurl {
         failEarly = true;
  -      pgpsigUrls = map (n: "${n}-tar-gz-asc.txt") baseUrls;
  -      pgpKeyFingerprint = "8B1F 4A9A DA73 D401 E308  5A0B 5FF0 6F29 BA1E 013B";
  -      inherit (src) urls outputHash outputHashAlgo;
  +      inherit (src)
  +        urls
  +        outputHash
  +        outputHashAlgo;
  +      fullOpts = {
  +        pgpsigUrls = map (n: "${n}-tar-gz-asc.txt") baseUrls;
  +        pgpKeyFingerprint = "8B1F 4A9A DA73 D401 E308  5A0B 5FF0 6F29 BA1E 013B";
  +      };
       };
     };
   
  
positive.code: }:
  
  let
    name = "chrony-3.3";
  
    baseUrls = [
      "https://download.tuxfamily.org/chrony/${name}"
  
negative.code: 
    src = fetchurl {
      urls = map (n: "${n}.tar.gz") baseUrls;
      multihash = "Qmev3vcNHk4yB4dy2YDhy3fngP8KsiCXDVbKVuubzuRwmX";
      hashOutput = false;
      sha256 = "af77e47c2610a7e55c8af5b89a8aeff52d9a867dd5983d848b52d374bc0e6b9f";
    };
    
    buildInputs = [
  