Cannot get ws messages using UMFuturesWebsocketClient

I use the code as belows, but I cannot get any ws response anywhere, and there is no error.
Could anyone help resolve this problem, or tell me how to get ws response

def message_handler(_, message):
    logging.info(message)
ws = UMFuturesWebsocketClient(on_message=message_handler)
ws.agg_trade(symbol="POWRUSDT")


time.sleep(5)


ws.agg_trade(
    symbol="POWRUSDT", action=UMFuturesWebsocketClient.ACTION_UNSUBSCRIBE
)
ws.stop()

Hey,
Try adding these lines of code before and see what happens:

from binance.lib.utils import config_logging
config_logging(logging, logging.DEBUG)