code: def add_comment(self, body, allow_create=False, allow_hashes=False,
                      summary=None):
          
          thread_id = self.lookup_thread_id()
          if not allow_create and not self.redis.exists(thread_id):
              raise ValueError('Tried to add comment to non-exist thread %s' % (
                  thread_id))
  
          comment = comments.SingleComment(
              self.user, datetime.datetime.now(datetime.timezone.utc), body, 
              summary=summary)
          lpush = self.redis.lpush(thread_id, comment.to_json())
          logging.debug('Pushing comment to redis returned %s', str(lpush))
          if self.ltrim:
              ltrim = self.redis.ltrim(thread_id, 0, self.ltrim)
              logging.debug('Redis ltrim returend %s', str(ltrim))
          else:
              ltrim = None
  
          return {'status': 'OK', 'lpush': lpush, 'ltrim': ltrim}
docs: Add comment as required by comments.CommentThread parent class.