anchor.diff:  
     tools = buildFromGitHub {
       version = 6;
  -    rev = "6c1c5e93cdc185a6ddf8f821166b3e631b0f8a72";
  -    date = "2018-08-24";
  +    rev = "8cc4e8a6f4841aa92a8683fca47bc5d64b58875b";
  +    date = "2018-07-27";
       owner = "golang";
       repo = "tools";
  -    sha256 = "xehSuyNUqDUdoa40naMyjDT8/KA7pCUp3sINvZv9Hp4=";
  +    sha256 = "0lw8pdsd6m3cgr8kq0ivib16wa94lhzi9sp59z8xmf9smas9c9vl";
       goPackagePath = "golang.org/x/tools";
   
       preConfigure = ''
  
positive.code: 
    go-ws-transport = buildFromGitHub {
      version = 6;
      rev = "v2.0.7";
      owner  = "libp2p";
      repo   = "go-ws-transport";
      sha256 = "MzUotaVAzkxE2QDNcR2SI+251gxyao7hJQHdWQkrsjQ=";
      propagatedBuildInputs = [
        go-libp2p-peer
        go-libp2p-transport
  
negative.code:     version = 6;
      owner = "pkg";
      repo = "sftp";
      rev = "v1.8.0";
      sha256 = "1jsklzbjhy324xqkkiyxx7d94lg91rrml4z7d3cz6z1006dyj7bw";
      propagatedBuildInputs = [
        crypto
        errors
  