anchor.diff:  
   
     urwid = buildPythonPackage (rec {
  -    name = "urwid-1.0.1";
  +    name = "urwid-1.0.2";
   
       doCheck = false;
   
       src = fetchurl {
         url = "http://excess.org/urwid/${name}.tar.gz";
  -      md5 = "828f7144b94920205e755c249d2e297f";
  +      md5 = "00542bbd15fae7ea60b02a7570edee2b";
       };
   
       meta = {
  
positive.code: 
      postInstall = ''
        wrapProgram $out/bin/alot \
          --prefix LD_LIBRARY_PATH : ${pkgs.notmuch}/lib:${pkgs.file511}/lib
      '';
  
      meta = {
  
negative.code: 
  
    afew = buildPythonPackage rec {
      rev = "6bb3915636aaf86f046a017ffffd9a4ef395e199";
      name = "afew-1.0_${rev}";
  
      src = fetchurl {
        url = "https://github.com/teythoon/afew/tarball/${rev}";
        name = "${name}.tar.bz";
        sha256 = "74926d9ddfa69534cfbd08a82f0acccab2c649558062654d5d2ff2999d201384";
      };
  
      propagatedBuildInputs = [ notmuch pkgs.dbacl ];
  