anchor.diff:    meta = with lib; {
       description = "Base library for scrapy's ItemLoader";
       homepage = "https://github.com/scrapy/itemloaders";
  +    changelog = "https://github.com/scrapy/itemloaders/raw/v${version}/docs/release-notes.rst";
       license = licenses.bsd3;
       maintainers = [ maintainers.marsam ];
     };
  
positive.code: 
  buildPythonPackage rec {
    pname = "itemloaders";
    version = "1.0.4";
    disabled = pythonOlder "3.6";
  
    # Tests not included in PyPI tarball
  
negative.code:     owner = "scrapy";
      repo = pname;
      rev = "v${version}";
      sha256 = "sha256-ueq1Rsuae+wz4eFc1O7luBVR4XWGbefpDr124H6j56g=";
    };
  
    propagatedBuildInputs = [ w3lib parsel jmespath itemadapter ];
  