anchor.diff:  , flaky
   , importlib-metadata
   , importlib-resources
  -, isPy27
  -, lib
   , pathlib2
  +, platformdirs
   , pytest-freezegun
   , pytest-mock
   , pytest-timeout
   , pytestCheckHook
  -, pythonOlder
   , setuptools-scm
   , six
  -, stdenv
   }:
   
   buildPythonPackage rec {
     pname = "virtualenv";
  -  version = "20.4.7";
  +  version = "20.7.2";
   
     src = fetchPypi {
       inherit pname version;
  -    sha256 = "14fdf849f80dbb29a4eb6caa9875d476ee2a5cf76a5f5415fa2f1606010ab467";
  +    sha256 = "9ef4e8ee4710826e98ff3075c9a4739e2cb1040de6a2a8d35db0055840dc96a0";
     };
   
     nativeBuildInputs = [
  
positive.code: { buildPythonPackage
  , appdirs
  , contextlib2
  , cython
  , distlib
  , fetchPypi
  
negative.code:   ];
  
    propagatedBuildInputs = [
      backports-entry-points-selectable
      distlib
      filelock
      platformdirs
      six
    ] ++ lib.optionals (pythonOlder "3.4" && !stdenv.hostPlatform.isWindows) [
      pathlib2
    ] ++ lib.optionals (pythonOlder "3.7") [
      importlib-resources
  