anchor.diff:  
       preCheck = ''
         export LANG="en_US.UTF-8"
  -      export LOCALE_ARCHIVE=${pkgs.glibcLocales}/lib/locale/locale-archive
  +      export LOCALE_ARCHIVE=${localePath}
       '';
   
       buildInputs = [ pytest py mock ];
  
positive.code:     };
  
      preBuild = ''
        export LOCALE_ARCHIVE=${pkgs.glibcLocales}/lib/locale/locale-archive
        export LC_ALL="en_US.UTF-8"
      '';
  
  
negative.code:   inherit (pkgs) fetchurl fetchsvn fetchgit stdenv unzip;
  
    # helpers
  
    # glibcLocales doesn't build on Darwin
    localePath = optionalString (! stdenv.isDarwin) "${pkgs.glibcLocales}/lib/locale/locale-archive";
  
    callPackage = pkgs.newScope pythonPackages;
  
  