docs: def _redis_client(opts):
      '''
      Connect to the redis host and return a StrictRedisCluster client object.
      If connection fails then return None.
      '''
      redis_host = opts.get("eauth_redis_host", "localhost")
      redis_port = opts.get("eauth_redis_port", 6379)
      try:
          return rediscluster.StrictRedisCluster(host=redis_host, port=redis_port, decode_responses=True)
      except rediscluster.exceptions.RedisClusterException as err:
          log.warning(
              'Failed to connect to redis at %s:%s - %s',
              redis_host, redis_port, err
          )
          return None