How to use the elasticsearch2.ConnectionError function in elasticsearch2

def client():
    global CLIENT
    if CLIENT is None:
        try:
            CLIENT = Elasticsearch(
                settings.ELASTIC_URI,
                request_timeout=settings.ELASTIC_TIMEOUT,
                retry_on_timeout=True,
                **settings.ELASTIC_KWARGS
            )
            logging.getLogger('elasticsearch').setLevel(logging.WARN)
            logging.getLogger('elasticsearch.trace').setLevel(logging.WARN)
            logging.getLogger('urllib3').setLevel(logging.WARN)
            logging.getLogger('requests').setLevel(logging.WARN)
            CLIENT.cluster.health(wait_for_status='yellow')
        except ConnectionError:
            message = (
                'The SEARCH_ENGINE setting is set to "elastic", but there '
                'was a problem starting the elasticsearch interface. Is '
                'elasticsearch running?'
            )
            if settings.SENTRY_DSN:
                try:
                    sentry.log_exception()
                    sentry.log_message(message)
                except AssertionError:  # App has not yet been initialized
                    logger.exception(message)
            else:
                logger.error(message)
            exit(1)
    return CLIENT