How to extract audio only using YoutubeDL class?

[chrismv48]

I want to simply extract the audio in MP3 format from youtube links, but I can't figure out how to do this without calling youtube-dl from the command line with the --extract-audio option. Is there a way to do this within the YoutubeDL class similar to examples given here?

Here's what I have so far, but it still creates an mp4 file.

import youtube_dl

# download using optimal audio settings
ydl_opts = {
    'format': 'bestaudio/best',
    'postprocessors': [{
        'key': 'FFmpegExtractAudio',
        'preferredcodec': 'mp3',
        'preferredquality': '192',
    }],
    'quiet': True,
    'restrictfilenames': True}

ydl = youtube_dl.YoutubeDL(ydl_opts)
ydl.download(['https://www.youtube.com/watch?v=Pnt2cy5MWyw'])

[dstftw]

I've just answered you on stackoverflow.
Post the output of script execution with quiet set to False.

[jaimeMF]

Closing since it seems that it's solved in stack overflow.