anchor.diff:      self = python36;
     };
   
  -  # Should eventually be moved inside Python interpreters.
  -  python-setup-hook = callPackage ../development/interpreters/python/setup-hook.nix { };
  -
  -  pypy = pypy27;
  -
     pypy27 = callPackage ../development/interpreters/python/pypy/2.7 {
       self = pypy27;
       python = python27.override{x11Support=true;};
       db = db.override { dbmSupport = true; };
     };
  +
  +  # Python package sets.
  +  python27Packages = lib.hiPrioSet (recurseIntoAttrs python27.pkgs);
  +  python34Packages = python34.pkgs;
  +  python35Packages = python35.pkgs;
  +  python36Packages = recurseIntoAttrs python36.pkgs;
  +  pypyPackages = pypy.pkgs;
  +
  +  # Should eventually be moved inside Python interpreters.
  +  python-setup-hook = callPackage ../development/interpreters/python/setup-hook.nix { };
   
     python2nix = callPackage ../tools/package-management/python2nix { };
   
  
positive.code:     databaseModule = perlPackages.DBDPg;
      sqitchModule = perlPackages.AppSqitch;
    };
  
    ### DEVELOPMENT / PYTHON MODULES
  
    # Python package sets.
  
    python27Packages = lib.hiPrioSet (recurseIntoAttrs python27.pkgs);
  
    python34Packages = python34.pkgs;
  
    python35Packages = python35.pkgs;
  
    python36Packages = recurseIntoAttrs python36.pkgs;
  
    pypyPackages = pypy.pkgs;
  
    ### DEVELOPMENT / R MODULES
  
  
negative.code:   python = python2;
    python2 = python27;
    python3 = python36;
    pypy = pypy27;
  
    # Python interpreter that is build with all modules, including tkinter.
    # These are for compatibility and should not be used inside Nixpkgs.
  