anchor.diff:  
     src = fetchPypi {
       inherit pname version;
  -    sha256 = "sha256-JgAQCulv/QgjNLN441VVD++LSlKab6TDT0cTCQXHQm0=";
  +    hash = "sha256-h49hfEEXk/FVwms5MwoJWhzFiETYi83HZ6Zcf8IJa1Q=";
     };
   
  -  # no longer compatible with sybil
  -  # https://github.com/simplistix/testfixtures/issues/169
  -  doCheck = false;
     checkInputs = [
       mock
       pytestCheckHook
  
positive.code: 
  buildPythonPackage rec {
    pname = "testfixtures";
    version = "6.18.3";
    format = "setuptools";
    # DO NOT CONTACT upstream.
    # https://github.com/simplistix/ is only concerned with internal CI process.
  
negative.code:   disabledTestPaths = [
      # Django is too much hasle to setup at the moment
      "testfixtures/tests/test_django"
    ];
  
    pytestFlagsArray = [
  