docs: def add_metadata(track_file, track_data):
      """
      Adds artist and title from the track data, and downloads the cover and embeds it in the MP3 tags.
      """
      # This needs some exception handling!
      # We don't always know what type the cover is!
      mp3 = mutagen.mp3.MP3(track_file)
  
      mp3['TPE1'] = mutagen.id3.TPE1(encoding=3, text=track_data.user['username'])
      mp3['TIT2'] = mutagen.id3.TIT2(encoding=3, text=track_data.title)
  
      cover_bytes = requests.get(track_data.artwork_url, stream=True).raw.read()
      mp3.tags.add(mutagen.id3.APIC(encoding=3, mime='image/jpeg', type=3, desc='Front cover', data=cover_bytes))
  
      mp3.save()