'Fetch lyrics, trying each source in turn. Return a string or
None if no lyrics were found.'

def get_lyrics(self, artist, title):

    for backend in self.backends:
        lyrics = backend.fetch(artist, title)
        if lyrics:
            self._log.debug(u'got    lyrics    from    backend:    {0}', backend.__class__.__name__)
            return _scrape_strip_cruft(lyrics, True)
