anchor.diff:      })
     ];
   
  +  checkInputs = [
  +    nose
  +  ];
  +
     propagatedBuildInputs = [
       six
     ];
  
positive.code: { lib
  , buildPythonPackage
  , fetchPypi
  , pythonOlder
  , substituteAll
  , six
  , withGraphviz ? true
  , graphviz
  , fontconfig
  # Tests
  , pytestCheckHook
  , nose
  }:
  
  buildPythonPackage rec {
  
negative.code:   # circular dependency anytree → graphviz → pango → glib → gtk-doc → anytree
    doCheck = withGraphviz;
  
    checkPhase = ''
      runHook preCheck
  
      nosetests
  
      runHook postCheck
    '';
  
    meta = with lib; {
      description = "Powerful and Lightweight Python Tree Data Structure";
  