anchor.diff:          wantedBy = [ "multi-user.target" ];
           after = [ "network-interfaces.target" ];
           environment = {
  -          PYTHONPATH =
  -            "${cfg.api.package}/lib/python2.7/site-packages:" +
  -            concatMapStringsSep ":" (f: f + "/lib/python2.7/site-packages") cfg.api.finders;
  +          PYTHONPATH = let
  +              aenv = pkgs.python.buildEnv.override {
  +                extraLibs = [ cfg.api.package pkgs.cairo ] ++ cfg.api.finders;
  +              };
  +            in "${aenv}/${pkgs.python.sitePackages}";
             GRAPHITE_API_CONFIG = graphiteApiConfig;
             LD_LIBRARY_PATH = "${pkgs.cairo}/lib";
           };
  
positive.code:         after = [ "network-interfaces.target" ];
          path = [ pkgs.perl ];
          environment = {
            PYTHONPATH = "${pkgs.python27Packages.graphite_web}/lib/python2.7/site-packages";
            DJANGO_SETTINGS_MODULE = "graphite.settings";
            GRAPHITE_CONF_DIR = configDir;
            GRAPHITE_STORAGE_DIR = dataDir;
          };
          serviceConfig = {
            ExecStart = ''
  
negative.code:   '';
  
    carbonEnv = {
      PYTHONPATH = let
        cenv = pkgs.python.buildEnv.override {
          extraLibs = [ pkgs.python27Packages.carbon ];
        };
        cenvPack =  "${cenv}/${pkgs.python.sitePackages}";
      # opt/graphite/lib contains twisted.plugins.carbon-cache
      in "${cenvPack}/opt/graphite/lib:${cenvPack}";
      GRAPHITE_ROOT = dataDir;
      GRAPHITE_CONF_DIR = configDir;
      GRAPHITE_STORAGE_DIR = dataDir;
  