old_contents: from unicore.comments.client.base import CommentServiceException
  from unicore.comments.client.commentclient import (
      CommentClient, Comment, CommentPage, UserBanned, CommentStreamNotOpen)
  
  
  __all__ = [
      'CommentServiceException',
      'Comment',
      'CommentClient',
      'CommentPage',
      'CommentStreamNotOpen',
      'UserBanned'
  ]
  
new_contents: from unicore.comments.client.base import CommentServiceException
  from unicore.comments.client.commentclient import (
      CommentClient, Comment, CommentPage, UserBanned, CommentStreamNotOpen,
      LazyCommentPage)
  
  
  __all__ = [
      'CommentServiceException',
      'Comment',
      'CommentClient',
      'CommentPage',
      'CommentStreamNotOpen',
      'LazyCommentPage',
      'UserBanned'
  ]
  
subject: add methods to check for and get previous/next page args