Sound is only supported in Windows, using the Winsound API.
Therefore, only .WAV files will work.

Playing Sound Files

from appJar import gui

# this function only returns once the sound finishes 
def blockingSound():
    app.playSound("sound.wav", wait=True)
    app.infoBox("Sound", "Finished sound")

# play the sound in a thread
def playSound():

with gui("SOUND") as app:
    app.button("PLAY", playSound)

Playing Built-In Sounds

Playing Musical Notes