anchor.diff:  { lib
   , buildPythonPackage
  -, pythonOlder
   , fetchFromGitHub
   , pytestCheckHook
  +, pythonOlder
   , pytz
   , simplejson
   }:
   
   buildPythonPackage rec {
     pname = "marshmallow";
  -  version = "3.13.0";
  +  version = "3.15.0";
  +  format = "setuptools";
   
     disabled = pythonOlder "3.6";
   
  
positive.code:     owner = "marshmallow-code";
      repo = pname;
      rev = version;
      sha256 = "sha256-tP/RKo2Hzxz2bT7ybRs9wGzq7TpsmzmOPi3BGuSLDA0=";
    };
  
    checkInputs = [
  
negative.code:   ];
  
    meta = with lib; {
      description = "Library for converting complex objects to and from simple Python datatypes";
      homepage = "https://github.com/marshmallow-code/marshmallow";
      license = licenses.mit;
      maintainers = with maintainers; [ cript0nauta ];
  