anchor.diff:        md5 = "90a82400074b50a9e73c3045ed9ac217";
       };
   
  -    buildInputs = [ virtualenv virtualenv-clone ];
  +    propagatedBuildInputs = [ virtualenv virtualenv-clone ];
   
       meta = with stdenv.lib; {
         description = "Tools to manage multiple virtualenvs written in pure python, a virtualenvwrapper rewrite";
  
positive.code: 
  
    # TODO
    # py.error.EACCES: [Permission denied]: mkdir('/homeless-shelter',)
    # builder for `/nix/store/0czwg0n3pfkmpjphqv1jxfjlgkbziwsx-python-tox-1.4.3.drv' failed with exit code 1
    # tox = buildPythonPackage rec {
    #   name = "tox-1.4.3";
    #
    #   buildInputs = [ py virtualenv ];
    #
    #   src = fetchurl {
    #     url = "https://pypi.python.org/packages/source/t/tox/tox-1.4.3.tar.gz";
    #     md5 = "3727d5b0600d92edf2229a7ce6a0f752";
    #   };
    # };
  
  
negative.code: 
    virtualenv-clone = buildPythonPackage rec {
      name = "virtualenv-clone-0.2.4";
  
      src = fetchurl {
        url = "https://pypi.python.org/packages/source/v/virtualenv-clone/${name}.tar.gz";
        md5 = "71168b975eaaa91e65559bcc79290b3b";
      };
  
      buildInputs = [pytest];
      propagatedBuildInputs = [virtualenv];
  
      # needs tox to run the tests
      doCheck = false;
  
      meta = with stdenv.lib; {
  