anchor.diff:      version = 3;
       owner = "gravitational";
       repo = "roundtrip";
  -    rev = "0.0.1";
  -    sha256 = "1gy8ahsjamr2ffslk2aydsw89f4kinv60rkwap20763fgaq7k3yl";
  +    rev = "0.0.2";
  +    sha256 = "12qqkm9pn398g5bfnaknynii4yqc2sa1i8qhzpp8jkdqf3bczcvz";
       propagatedBuildInputs = [
         trace
       ];
  
positive.code: 
    mongo-tools = buildFromGitHub {
      version = 3;
      rev = "8c2e8c7ee26eb04b3f7f86376a31a491cab400e6";
      owner  = "mongodb";
      repo   = "mongo-tools";
      sha256 = "08dygf4m0aj6w5vb51k2ddfqfadnmwz7134s01nqfsdj1vsabps4";
      buildInputs = [
        crypto
        escaper
  
negative.code: 
    ugorji_go = buildFromGitHub {
      version = 3;
      date = "2017-11-01";
      rev = "50189f05eaf5a0c17e5084eb8f7fb91e23699840";
      owner = "ugorji";
      repo = "go";
      sha256 = "1q74fpsx83a312az2rrsf7j83j6j6nkq02xyws64dv0rvya5k1ll";
      goPackageAliases = [
        "github.com/hashicorp/go-msgpack"
      ];
  