def _make_abspath(self, relative_path):
        return os.path.join(self._root, relative_path)
Builds a subclass model for the given backend
dataset/ETHPy150Open bloomberg/phabricator-tools/py/abd/abdt_fs.py/Accessor._make_abspath--crossover with--dataset/ETHPy150Open willhardy/django-seo/rollyourown/seo/options.py/Options._add_backend