def classifiers(self):
        """this needs more intelligence, probably splitting the classifiers from _pkg_data
        and only adding defaults when no explicit entries were provided.
        Add explicit Python versions in sync with tox.env generation based on python_requires?
        """
        attr = '_' + sys._getframe().f_code.co_name
        if not hasattr(self, attr):
            setattr(self, attr, self._setup_classifiers())
        return getattr(self, attr)
this needs more intelligence, probably splitting the classifiers from _pkg_data
        and only adding defaults when no explicit entries were provided.
        Add explicit Python versions in sync with tox.env generation based on python_requires?
        
dynaconf/vendor/ruamel/yaml/setup.py