docs: def comments(self):
          '''Looks through the last 3 messages and returns those comments.'''
          if self.cache['comments']: return self.cache['comments']
          comments = []
          for message in self.messages[0:3]:
              comment_xml = self.bc.comments(message.id)
              for comment_node in ET.fromstring(comment_xml).findall("comment"):
                  comments.append(Comment(comment_node))
          comments.sort()
          comments.reverse()
          self.cache['comments'] = comments
          return self.cache['comments']