def _key_to_file(self, key):
        path = hashlib.md5(force_bytes(key)).hexdigest()
        path = os.path.join(path[:2], path[2:4], path[4:])
        return os.path.join(self._dir, path)
Convert the filename into an md5 string. We'll turn the first couple
dataset/ETHPy150Open cloudera/hue/desktop/core/ext-py/Django-1.6.10/django/core/cache/backends/filebased.py/FileBasedCache._key_to_file