anchor.diff:  
     # for the optional dependency ipykernel, only versions < 6 are
     # supported, so it's not included in the tests, and not propagated
  -  propagatedBuildInputs = [ traits apptools setuptools ];
  +  propagatedBuildInputs = [
  +    traits
  +    apptools
  +    setuptools
  +  ];
   
     preCheck = ''
       export HOME=$PWD/HOME
  
positive.code:     pytestCheckHook
    ];
  
    meta = with lib; {
      description = "Framework for building applications whose functionalities can be extended by adding 'plug-ins'";
      homepage = "https://github.com/enthought/envisage";
      maintainers = with lib.maintainers; [ knedlsepp ];
      license = licenses.bsdOriginal;
    };
  }
  
negative.code: { lib
  , apptools
  , buildPythonPackage
  , fetchPypi
  , ipython
  , pytestCheckHook
  , pythonAtLeast
  , pythonOlder
  , setuptools
  , traits
  }:
  
  buildPythonPackage rec {
    pname = "envisage";
    version = "6.0.1";
    format = "setuptools";
  
    disabled = pythonOlder "3.6";
  
    src = fetchPypi {
      inherit pname version;
  