Refreshes the internal lookup table if necessary.

def refresh(self):
        """
        Refreshes the internal lookup table if necessary.
        """
        try:
            self._private_to_public = self.cloud_discovery.discover_nodes()
        except Exception as ex:
            self.logger.warning("Failed to load addresses from Hazelcast.cloud: {}".format(ex.args[0]),
                                extra=self._logger_extras)