code: def format(self, subtitles):
          
          logger.debug('Formatting subtitles (id=%s) with %s',
              subtitles.id, self.__class__.__name__)
          return self._format(subtitles).encode('utf-8')
docs: Turn a string containing the subs xml document into the formatted
          subtitle string
  
          @param str|crunchyroll.models.StyledSubtitle sub_xml_text
          @return str