anchor.diff:  
     google-cloud-go = buildFromGitHub {
       version = 3;
  -    date = "2017-09-07";
  -    rev = "f0bd45f271811f1e46cf7e787932e1db593b0dc3";
  +    date = "2017-09-11";
  +    rev = "5a9e19d4e1e41a734154e44a2132b358afb49a03";
       owner = "GoogleCloudPlatform";
       repo = "google-cloud-go";
  -    sha256 = "1lawa7npr9x7x0fakpyis2nhq76ca6cpnsnvb2zzqniz8z399hfv";
  +    sha256 = "1psf244f5fpn64qrz1902a0p1ghrhphzmpix3wgi0f4nrj9x2czn";
       goPackagePath = "cloud.google.com/go";
       goPackageAliases = [
         "google.golang.org/cloud"
  
positive.code:     propagatedBuildInputs = [
        protobuf
      ];
      rev = "v3.2.7";
      sha256 = "1ra41x4sw0zk544cbffadb31kl3vnqgww56f718hrfa462xbxyx0";
      version = 3;
    };
  
    etree = buildFromGitHub {
  
negative.code: 
    consul-template = buildFromGitHub {
      version = 3;
      rev = "v0.19.3";
      owner = "hashicorp";
      repo = "consul-template";
      sha256 = "0f1pykbh0q4l6vnkdcf891hb1c89jjjmlx0b1cdjaixhyf55x001";
  
      propagatedBuildInputs = [
        consul_api
  