anchor.diff:  
     text = buildFromGitHub {
       version = 3;
  -    rev = "57961680700a5336d15015c8c50686ca5ba362a4";
  -    date = "2017-12-04";
  +    rev = "be25de41fadfae372d6470bda81ca6beb55ef551";
  +    date = "2017-12-07";
       owner = "golang";
       repo = "text";
  -    sha256 = "11f7256vzmmapdlcbr5f1na9fqdlvc4fa3yzi1ld0lsshjgqbn8m";
  +    sha256 = "1q3fc38a49z8h81hq89764q8877k8m4n2vfs4y99z00dhi0pnjnv";
       goPackagePath = "golang.org/x/text";
       excludedPackages = "\\(cmd\\|test\\)";
     };
  
positive.code: 
    google-cloud-go = buildFromGitHub {
      version = 3;
      date = "2017-12-06";
      rev = "3051b919da3b8d62bc3a57ab4b353ca1c72402d5";
      owner = "GoogleCloudPlatform";
      repo = "google-cloud-go";
      sha256 = "1qnc7nxbb9m7hmdh6mw4kxrz79a57ihs8mwhjk31hmaly5w0c1g3";
      goPackagePath = "cloud.google.com/go";
      goPackageAliases = [
        "google.golang.org/cloud"
  
negative.code: 
      excludedPackages = "\\(test\\|benchmark\\|example\\|bridge\\)";
      meta.useUnstable = true;
      date = "2017-12-07";
    };
  
    etcd_client = etcd.override {
  