anchor.diff:  
     ugorji_go = buildFromGitHub {
       version = 2;
  -    date = "2017-01-07";
  -    rev = "ded73eae5db7e7a0ef6f55aace87a2873c5d2b74";
  +    date = "2017-01-21";
  +    rev = "d23841a297e5489e787e72fceffabf9d2994b52a";
       owner = "ugorji";
       repo = "go";
  -    sha256 = "1kzfkvz8h44j9n9ys7nd82v1nmq6dlfq2vmm3anhmjl3nkr4wldg";
  +    sha256 = "1lqb1924ibmfxypv5r97r3kxhykkga87n5f3mcwqbx0v3y0ypapi";
       goPackageAliases = [ "github.com/hashicorp/go-msgpack" ];
     };
   
  
positive.code: 
    aws-sdk-go = buildFromGitHub {
      version = 2;
      rev = "v1.6.14";
      owner  = "aws";
      repo   = "aws-sdk-go";
      sha256 = "1qkvkpwl3w5wbkm0fqjqh8rp3aij69bdpsazb8yzfwyjfghk6m4k";
      excludedPackages = "\\(awstesting\\|example\\)";
      buildInputs = [
        tools
  
negative.code:     version = 2;
      owner = "ncw";
      repo = "rclone";
      rev = "9fdeb823282e5b6af943b62a644af932c0bcc7ba";
      sha256 = "12b9nasgja7jp710dwidr8370sa74n7k5b4glqkxmpipy5mjd2w2";
      propagatedBuildInputs = [
        aws-sdk-go
        cobra
  