anchor.diff:  
     go-multihash = buildFromGitHub {
       version = 2;
  -    rev = "3922c539dc610bb88fdbb2bcd1108802bcd7ea50";
  +    rev = "5be2115933c26c6ae0c4b9c5887a44d8ae5bb753";
       owner  = "multiformats";
       repo   = "go-multihash";
  -    sha256 = "0jbpmpm5ij64j6073c133dl4c0n3bh5m3rknyakclgd9qbb031vj";
  +    sha256 = "0qj0pkjqpdadsh0c20mvgfwd8mx4dprb5c97i063bsrk9jyxsdy6";
       goPackageAliases = [ "github.com/jbenet/go-multihash" ];
       propagatedBuildInputs = [
         crypto
         go-base58
       ];
  -    date = "2016-11-10";
  +    date = "2016-12-12";
     };
   
     go-multipart-files = buildFromGitHub {
  
positive.code: 
    btree = buildFromGitHub {
      version = 2;
      rev = "925471ac9e2131377a91e1595defec898166fe49";
      owner  = "google";
      repo   = "btree";
      sha256 = "13j2c46rzbl6zdyiwg4ddgpgfan31y20x0dy2zc93809cvdsfy3l";
      date = "2016-10-05";
    };
  
    bufio_v1 = buildFromGitHub {
  
negative.code: 
    net = buildFromGitHub {
      version = 2;
      rev = "cfae461cedfdcab6e261a26eb77db53695623303";
      date = "2016-12-13";
      owner  = "golang";
      repo   = "net";
      sha256 = "16m2x6qq31hgzx00w8v3fdlkj1nd9id7mzd7d6cfaq7lvrd15xd6";
      goPackagePath = "golang.org/x/net";
      goPackageAliases = [
        "github.com/hashicorp/go.net"
  