anchor.diff:      if isPy34 then "python34" else
       if isPyPy then "pypy" else "";
   
  -  modules = python.modules or { readline = null; sqlite3 = null; curses = null; curses_panel = null; ssl = null; crypt = null; };
  -
  -pythonPackages = modules // import ./python-packages-generated.nix {
  -  inherit pkgs python;
  -  inherit (pkgs) stdenv fetchurl;
  -  self = pythonPackages;
  -} //
  -
  +  modules = python.modules or {
  +    readline = null;
  +    sqlite3 = null;
  +    curses = null;
  +    curses_panel = null;
  +    ssl = null;
  +    crypt = null;
  +  };
  +
  +  pythonPackages = modules // import ./python-packages-generated.nix {
  +    inherit pkgs python;
  +    inherit (pkgs) stdenv fetchurl;
  +    self = pythonPackages;
  +  }
   # Python packages for all python versions
  -rec {
  +// rec {
   
     inherit python isPy26 isPy27 isPy33 isPy34 isPyPy isPy3k pythonName;
     inherit (pkgs) fetchurl fetchsvn fetchgit stdenv unzip;
   
     # helpers
   
  -  callPackage = callPackageWith (pkgs // pythonPackages);
  +  callPackage = pkgs.newScope pythonPackages;
   
     # global distutils config used by buildPythonPackage
     distutils-cfg = callPackage ../development/python-modules/distutils-cfg { };
  
positive.code:   };
  
    h5py = callPackage ../development/python-modules/h5py {
      inherit (pkgs) stdenv fetchurl;
      inherit python buildPythonPackage cython numpy;
      hdf5 = pkgs.hdf5.override { mpi = null; };
    };
  
  
negative.code: 
  
  
  }); in pythonPackages