def _get_root_from_cache(self, directory):
        if directory in self._roots_cache:
            return directory
        if os.path.dirname(directory) == directory:
            return None
        return self._get_root_from_cache(os.path.dirname(directory))
a directory is considered cached if it's the project root or a subdirectory of that project root.
dataset/ETHPy150Open pindexis/qfc/qfc/dirhandler.py/CVSHandler._get_root_from_cache