def uri(self):
        """Connection string to pass to `~pymongo.mongo_client.MongoClient`."""
        if self._uds_path:
            uri = 'mongodb://%s' % (quote_plus(self._uds_path),)
        else:
            uri = 'mongodb://%s' % (format_addr(self._address),)
        return uri + '/?ssl=true' if self._ssl else uri