[Python] What does 'Error: AudioFileOpen failed ('wht?')' from afplay mean?

I am trying to run this code but it causes the following error:

Error: AudioFileOpen failed ('wht?')
​

Here's my code. It's running on a Mac and with a folder of mp3 files:

import os
def randomShuffleSongFromFolder(folderPath):
try:
music = os.listdir(folderPath)
except:
print('Error-Music folder not found')
exit()
random.shuffle(music)
music.remove('.DS_Store')
print(folderPath)
print(music)
for song in music:
os.system('afplay "' + song + '"')
if __name__ == '__main__':
print(os.listdir('/Users/isaac_lims_macbook_air/Desktop/davidMusic'))
randomShuffleSongFromFolder('/Users/isaac_lims_macbook_air/Desktop/MusicExample/')

Continue reading...