anchor.diff:  
   
     afew = buildPythonPackage rec {
  -    name = "afew-1.0pre";
  -    src = fetchurl {
  -      url = "https://github.com/teythoon/afew/tarball/master";
  +    rev = "6bb3915636aaf86f046a017ffffd9a4ef395e199";
  +    name = "afew-1.0_${rev}";
  +
  +    src = fetchurl {
  +      url = "https://github.com/teythoon/afew/tarball/${rev}";
         name = "${name}.tar.bz";
  -      sha256 = "949710f8dcf503f42f2a2d77ea71e48ccf70155a764f75ad29cc93edc120809b";
  +      sha256 = "74926d9ddfa69534cfbd08a82f0acccab2c649558062654d5d2ff2999d201384";
       };
   
       propagatedBuildInputs = [ notmuch pkgs.dbacl ];
  
positive.code: 
  
    urwid = buildPythonPackage (rec {
      name = "urwid-1.0.1";
  
      doCheck = false;
  
      src = fetchurl {
        url = "http://excess.org/urwid/${name}.tar.gz";
        md5 = "828f7144b94920205e755c249d2e297f";
      };
  
      meta = {
  
negative.code:       description = "A concurrent networking library for Python";
      };
    };
  
  
    flake8 = buildPythonPackage (rec {
      name = "flake8-1.4";
  
      src = fetchurl {
        url = "http://pypi.python.org/packages/source/f/flake8/${name}.tar.gz";
        md5 = "64acc2c905178f6d6817d88574407fb5";
      };
  
      doCheck = false;
  
      meta = {
        description = "code checking using pep8 and pyflakes.";
        homepage = http://pypi.python.org/pypi/flake8;
        license = pkgs.lib.licenses.mit;
        maintainers = [ stdenv.lib.maintainers.garbas ];
        platforms = python.meta.platforms;
      };
    });
  
  
    flask = buildPythonPackage {
  