anchor.diff:    # circular dependency anytree → graphviz → pango → glib → gtk-doc → anytree
     doCheck = withGraphviz;
   
  -  checkPhase = ''
  -    runHook preCheck
  +  checkInputs = [ pytestCheckHook nose ];
   
  -    nosetests
  -
  -    runHook postCheck
  -  '';
  +  pytestFlagsArray = lib.optionals (pythonOlder "3.4") [
  +    # Use enums, which aren't available pre-python3.4
  +    "--ignore=tests/test_resolver.py"
  +    "--ignore=tests/test_search.py"
  +  ];
   
     meta = with lib; {
       description = "Powerful and Lightweight Python Tree Data Structure";
  
positive.code:     })
    ];
  
    checkInputs = [
      nose
    ];
  
    propagatedBuildInputs = [
      six
    ];
  
negative.code: { lib
  , buildPythonPackage
  , fetchPypi
  , pythonOlder
  , substituteAll
  , six
  , withGraphviz ? true
  , graphviz
  , fontconfig
  # Tests
  , pytestCheckHook
  , nose
  }:
  
  buildPythonPackage rec {
  