anchor.diff:  
     rainbowstream = buildPythonPackage rec {
       name = "rainbowstream-${version}";
  -    version = "1.2.7";
  +    version = "1.3.1";
   
       src = pkgs.fetchurl {
         url    = "https://pypi.python.org/packages/source/r/rainbowstream/${name}.tar.gz";
  -      sha256 = "1jvv07w9n7ca251l92alm2yq9w82sb7lvxz6if3gc3nbqzc587rf";
  +      sha256 = "0dhhgr0ww4x85pgl6mzp327sy4v6mv6hz3wvnsrwl0knkxknbadv";
       };
   
       doCheck = false;
  
positive.code: 
      buildInputs = with self; [
        pkgs.libjpeg pkgs.freetype pkgs.zlib pkgs.glibcLocales
        pillow twitter pyfiglet requests arrow dateutil modules.readline pysocks
      ];
  
      meta = {
  
negative.code:       clib=$out/${python.sitePackages}/rainbowstream/image.so
        substituteInPlace rainbowstream/c_image.py \
          --replace @CLIB@ $clib
        sed -i 's/requests.*"/requests"/' setup.py
      '';
  
      preBuild = ''
  