code: def top_commenters(self, num):
          
          num = min(num, len(self.commenters))
          if num <= 0:
              return ''
  
          top_commenters = sorted(
              iteritems(self.commenters),
              key=lambda x: (-sum(y.score for y in x[1]),
                             -len(x[1]), str(x[0])))[:num]
  
          retval = self.post_header.format('Top Commenters')
          for author, comments in top_commenters:
              retval += '1. {} ({}, {} comment{})\n'.format(
                  self._user(author),
                  self._points(sum(x.score for x in comments)),
                  len(comments), 's' if len(comments) != 1 else '')
          return '{}\n'.format(retval)
docs: Return a markdown representation of the top commenters.