docs: def metalarchives(song):
      """
      Returns the lyrics found in MetalArchives for the specified mp3 file or an
      empty string if not found.
      """
      artist = normalize(song.artist)
      title = normalize(song.title)
  
      url = 'https://www.metal-archives.com/search/ajax-advanced/searching/songs'
      url += f'/?songTitle={title}&bandName={artist}&ExactBandMatch=1'
      soup = get_url(url, parser='json')
      if not soup:
          return ''
  
      song_id_re = re.compile(r'lyricsLink_([0-9]*)')
      ids = set(re.search(song_id_re, a) for sub in soup['aaData'] for a in sub)
      if not ids:
          return ''
  
      if None in ids:
          ids.remove(None)
      ids = map(lambda a: a.group(1), ids)
      for song_id in ids:
          url = 'https://www.metal-archives.com/release/ajax-view-lyrics/id/{}'
          lyrics = get_url(url.format(song_id), parser='html')
          lyrics = lyrics.get_text().strip()
          if not re.search('lyrics not available', lyrics):
              return lyrics
  
      return ''