anchor.diff:  
       excludedPackages = "\\(test\\|benchmark\\|example\\|bridge\\)";
       meta.useUnstable = true;
  -    date = "2017-10-19";
  +    date = "2017-10-20";
   
       preBuild = ''
         pushd go/src/$goPackagePath
  
positive.code: 
    decimal = buildFromGitHub {
      version = 3;
      rev = "ad668bb36961e1e1ac005e514b610e41573603bf";
      owner  = "shopspring";
      repo   = "decimal";
      sha256 = "0jd6xaa50lncgvqa12ddcvwxp00jb19z2g4n3dpn76s1qibx6v1l";
      date = "2017-10-10";
    };
  
    demangle = buildFromGitHub {
  
negative.code: 
    netlink = buildFromGitHub {
      version = 3;
      rev = "b2de5d10e38ecce8607e6b438b6d174f389a004e";
      owner  = "vishvananda";
      repo   = "netlink";
      sha256 = "0485hf122i93j4nv2005vq204rvsyqn04d9ryj6n3a1garra8ja6";
      date = "2017-10-20";
      propagatedBuildInputs = [
        netns
      ];
  