it is not working because of the flag, which is winsound.SND_ASYNC, but there aren't any error messages.
import winsound
winsound.PlaySound('C:/Users/aaa/Desktop/alarm.wav', winsound.SND_FILENAME | winsound.SND_LOOP | winsound.SND_ASYNC)
However, blow code is working... it played the sound of "alarm.wav"
import winsound
winsound.PlaySound('C:/Users/aaa/Desktop/alarm.wav', winsound.SND_FILENAME)
I don't know why it is...
