docs: def _show_one(audio_file):
      "given an audio file, print out the artist, title and some audio attributes of the song"
      print 'File:        ', audio_file
      pytrack = track.track_from_filename(audio_file)
      print 'Artist:      ', pytrack.artist if hasattr(pytrack, 'artist') else 'Unknown'
      print 'Title:       ', pytrack.title if hasattr(pytrack, 'title') else 'Unknown'
      print 'Track ID:    ', pytrack.id
      print 'Tempo:       ', pytrack.tempo
      print 'Energy:       %1.3f %s' % (pytrack.energy, _bar(pytrack.energy))
      if not pytrack.valence:
          # Track hasn't had latest attributes computed. Force an upload.
          pytrack = track.track_from_filename(audio_file, force_upload=True)
      print 'Valence:      %1.3f %s' % (pytrack.valence, _bar(pytrack.valence)) 
      print 'Acousticness: %1.3f %s' % (pytrack.acousticness, _bar(pytrack.acousticness))
      print