How to use the c2cwsgiutils.stats.set_gauge function in c2cwsgiutils

def list(self):
        count = 0
        while True:
            queues = self._master.xreadgroup(
                groupname=STREAM_GROUP,
                consumername=CONSUMER_NAME,
                streams={self._name: ">"},
                count=1,
                block=round(self._timeout_ms),
            )

            if not queues:
                queues = self._claim_olds()
                if queues is None:
                    stats.set_gauge(["redis", self._name_str, "nb_messages"], 0)
                    stats.set_gauge(["redis", self._name_str, "pending"], 0)
                if queues is None and self._stop_if_empty:
                    break
            if queues:
                for redis_message in queues:
                    queue_name, queue_messages = redis_message
                    assert queue_name == self._name
                    for message in queue_messages:
                        id_, body = message
                        try:
                            tile = decode_message(body[b"message"], from_redis=True, sqs_message=id_)
                            yield tile
                        except Exception:
                            logger.warning("Failed decoding the Redis message", exc_info=True)
                            stats.increment_counter(["redis", self._name_str, "decode_error"])
                        count += 1

for message in queue_messages:
                        id_, body = message
                        try:
                            tile = decode_message(body[b"message"], from_redis=True, sqs_message=id_)
                            yield tile
                        except Exception:
                            logger.warning("Failed decoding the Redis message", exc_info=True)
                            stats.increment_counter(["redis", self._name_str, "decode_error"])
                        count += 1

                if count % 10 == 0:
                    stats.set_gauge(
                        ["redis", self._name_str, "nb_messages"], self._slave.xlen(name=self._name)
                    )
                    pending = self._slave.xpending(self._name, STREAM_GROUP)
                    stats.set_gauge(["redis", self._name_str, "pending"], pending["pending"])

def get_status(self):
        """
        Returns a map of stats
        """
        nb_messages = self._slave.xlen(self._name)
        pending = self._slave.xpending(self._name, STREAM_GROUP)
        tiles_in_error = self._get_errors()

        stats.set_gauge(["redis", self._name_str, "nb_messages"], nb_messages)
        return {
            "Approximate number of tiles to generate": nb_messages,
            "Approximate number of generating tiles": pending["pending"],
            "Tiles in error": ", ".join(tiles_in_error),
        }

if queues:
                for redis_message in queues:
                    queue_name, queue_messages = redis_message
                    assert queue_name == self._name
                    for message in queue_messages:
                        id_, body = message
                        try:
                            tile = decode_message(body[b"message"], from_redis=True, sqs_message=id_)
                            yield tile
                        except Exception:
                            logger.warning("Failed decoding the Redis message", exc_info=True)
                            stats.increment_counter(["redis", self._name_str, "decode_error"])
                        count += 1

                if count % 10 == 0:
                    stats.set_gauge(
                        ["redis", self._name_str, "nb_messages"], self._slave.xlen(name=self._name)
                    )
                    pending = self._slave.xpending(self._name, STREAM_GROUP)
                    stats.set_gauge(["redis", self._name_str, "pending"], pending["pending"])