new_contents: import pafy
  
  from filemanager import get_workingdir
  
  class YouTube(object):
      def __init__(self, url):
          self.url = url
          self._metadata(url)
  
      def create_audiostream_dict(self, audiostreams):
          """
          Creates audiostream dictionary using bitrate as key
          """
          audiostream_dict = dict()
          i = 0
          for audiostream in audiostreams:
              _key = '-'.join([audiostream.bitrate, audiostream.extension])
              audiostream_dict[_key] = i
              i+=1
          return audiostream_dict
  
      def _metadata(self, url):
          """
          Gets the video metadata from url
          """
          video = pafy.new(url)
          self.video = video
          self.title = video.title
          self.duration = video.duration
          self.audio_available = self.create_audiostream_dict(video.audiostreams)
          self.audiostreams = video.audiostreams
  
      def download_audio(self, audiostream_key):
          """
          Downloads audio file from youtube in the specified audiostream, if
          the audiostream size/format is not specified, downloads default audio
          """
          audio_index = lambda : self.audio_available.get(audiostream_key)
          tmp_dir = get_workingdir()
          self.audiostreams[audio_index()].download(filepath=tmp_dir)
  
  """if __name__ == '__main__':
      yt = YouTube("https://www.youtube.com/watch?v=PYQGU6HWSXw")
      yt.download_audio(audiostream_key='128k-m4a')
  """
  
subject: Add audio downloader for youtube