old_contents: from __future__ import absolute_import
  
  
  class Context(object):
      """Represent a context.
  
      This includes metadata such as message ID.
      """
      __slots__ = (
          'message_id',
          'message',
      )
  
      def __init__(self, message_id, message):
          self.message_id = message_id
          self.message = message
  
new_contents: from __future__ import absolute_import
  
  from collections import namedtuple
  
  Context = namedtuple('Context', 'message_id message')
  
subject: Make Context a namedtuple