old_contents: from pydub import AudioSegment
  from io import BytesIO
  
  
  def convert_to_ogg(f):
      bio = BytesIO()
  
      AudioSegment.from_file(f).export(bio, format='ogg', codec='libopus')
      bio.seek(0)
  
      return bio
  
new_contents: from pydub import AudioSegment
  from io import BytesIO
  
  
  def convert_to_ogg(f):
      bio = BytesIO()
  
      (AudioSegment.from_file(f)
                   .set_channels(1)  # for compatibility with Android
                   .export(bio, format='ogg', codec='libopus'))
      bio.seek(0)
  
      return bio
  
subject: Fix playback on Android