anchor.diff:  
     circonus-gometrics = buildFromGitHub {
       version = 2;
  -    date = "2017-01-31";
  -    rev = "a2c28f079ec3d4fdc17ed577cca75bee88a2da25";
  +    date = "2017-02-01";
  +    rev = "fb2909576d0526b70e3efa0ef10737b92f57f15a";
       owner  = "circonus-labs";
       repo   = "circonus-gometrics";
  -    sha256 = "01nigc7y1fjkhq4jwhnrd6l0ibdh19yghd639cd5xrzkf294g2an";
  +    sha256 = "1hdgh4rfsss60x6ml8iqzp5byn2lm4v7zni9jj2zjwdzzd1b0f8b";
       propagatedBuildInputs = [
         circonusllhist
         go-retryablehttp
  
positive.code: 
    dns = buildFromGitHub {
      version = 2;
      rev = "99f84ae56e75126dd77e5de4fae2ea034a468ca1";
      date = "2017-01-30";
      owner  = "miekg";
      repo   = "dns";
      sha256 = "1nbidgs2fij4kpbgxjmga1m8wi01r5vw3hc69jqlszhfgbl059p4";
    };
  
    weppos-dnsimple-go = buildFromGitHub {
  
negative.code:     version = 2;
      owner = "pkg";
      repo = "sftp";
      rev = "bf1c2bb0012cdea62d6c5ae7212a1bb04cfa4d89";
      date = "2017-01-31";
      sha256 = "0ls6vylv56pxbill1raf61js0i1p787mrdnmm271sqkbix53irq9";
      propagatedBuildInputs = [
        crypto
        errors
  