anchor.diff:  { lib
   , buildPythonPackage
   , fetchPypi
  +, isPy27
   , pytest
   , jdcal
   , et_xmlfile
  
positive.code: buildPythonPackage rec {
    pname = "openpyxl";
    version = "3.0.0";
  
    src = fetchPypi {
      inherit pname version;
  
negative.code:     license = lib.licenses.mit;
      maintainers = with lib.maintainers; [ lihop sjourdois ];
    };
  }
  