code: def mark_as_read(self, messages, unread=False):
          
          ids = []
          if isinstance(messages, Inboxable):
              ids.append(messages.fullname)
          elif hasattr(messages, '__iter__'):
              for msg in messages:
                  if not isinstance(msg, Inboxable):
                      msg = 'Invalid message type: {0}'.format(type(msg))
                      raise ClientException(msg)
                  ids.append(msg.fullname)
          else:
              msg = 'Invalid message type: {0}'.format(type(messages))
              raise ClientException(msg)
          # pylint: disable=W0212
          retval = self.reddit_session._mark_as_read(ids, unread=unread)
          # pylint: enable=W0212
          return retval
docs: Mark message(s) as read or unread.
  
          :returns: The json response from the server.