anchor.diff:    , libGLU
     , libX11
     , six
  +  , pytest
  +  , makeFontsConf
  +  , freefont_ttf
   }:
   
  -let 
  +let
     pythonocc-core-cadquery = stdenv.mkDerivation {
       pname = "pythonocc-core-cadquery";
       version = "0.18.2";
  
positive.code: in
    buildPythonPackage rec {
      pname = "cadquery";
      version = "2.0RC0";
    
      src = fetchFromGitHub {
        owner = "CadQuery";
        repo = pname;
        rev = version;
        sha256 = "1xgd00rih0gjcnlrf9s6r5a7ypjkzgf2xij2b6436i76h89wmir3";
      };
    
      buildInputs = [
        opencascade
      ];
    
      propagatedBuildInputs = [
        pyparsing
        pythonocc-core-cadquery
      ];
    
      # Build errors on 2.7 and >=3.8 (officially only supports 3.6 and 3.7).
      disabled = !(isPy3k && (pythonOlder "3.8"));
    
      meta = with lib; {
        description = "Parametric scripting language for creating and traversing CAD models";
        homepage = "https://github.com/CadQuery/cadquery";
  
negative.code:       sha256 = "07zmiiw74dyj4v0ar5vqkvk30wzcpjjzbi04nsdk5mnlzslmyi6c";
      };
  
      nativeBuildInputs = [
        cmake
        swig
        ninja
  