anchor.diff:  , fetchPypi
   , six
   , traceback2
  +, pythonAtLeast
   }:
   
   buildPythonPackage rec {
  
positive.code: 
    propagatedBuildInputs = [ six traceback2 ];
  
    # # 1.0.0 and up create a circle dependency with traceback2/pbr
    doCheck = false;
  
    postPatch = ''
      # argparse is needed for python < 2.7, which we do not support anymore.
      substituteInPlace setup.py --replace "argparse" ""
  
      # # fixes a transient error when collecting tests, see https://bugs.launchpad.net/python-neutronclient/+bug/1508547
      sed -i '510i\        return None, False' unittest2/loader.py
      # https://github.com/pypa/packaging/pull/36
      sed -i 's/version=VERSION/version=str(VERSION)/' setup.py
  
negative.code: 
    meta = with lib; {
      description = "A backport of the new features added to the unittest testing framework";
      homepage = "https://pypi.org/project/unittest2/";
      license = licenses.bsd0;
      # AttributeError: module 'collections' has no attribute 'MutableMapping'
      broken = pythonAtLeast "3.10";
    };
  }
  