Returns 16-digit numeric hash of the redis key

def _hashed_key(self):
        """ Returns 16-digit numeric hash of the redis key """
        return abs(int(hashlib.md5(
            self.key_prefix.encode('utf8')
        ).hexdigest(), 16)) % (10 ** (
            self._size_mod if hasattr(self, '_size_mod') else 5))