anchor.diff:  
   buildPythonPackage rec {
     pname = "towncrier";
  -  version = "19.9.0";
  +  version = "21.3.0";
   
     src = fetchPypi {
       inherit pname version;
  -    sha256 = "19916889879353a8863f3de8cb1ef19b305a0b5cfd9d36159d76ca2fef08e9aa";
  +    sha256 = "6eed0bc924d72c98c000cb8a64de3bd566e5cb0d11032b73fcccf8a8f956ddfe";
     };
   
     propagatedBuildInputs = [
  
positive.code: 
    # zope.interface collision
    doCheck = !isPy27;
    checkInputs = [ git twisted pytestCheckHook ];
    pythonImportsCheck = [ "towncrier" ];
  
    meta = with lib; {
  
negative.code: , click-default-group
  , incremental
  , jinja2
  , mock
  , pytestCheckHook
  , toml
  , twisted
  