old_contents: # -*- coding: utf-8 -*-
  
  
  class CircleCraterError(Exception):
      def __init__(self, message_str = ''):
          message = message_str
  
new_contents: # -*- coding: utf-8 -*-
  
  
  class CircleCraterError(Exception):
      def __init__(self, message_str = ''):
          self.message = message_str
  
subject: define error class init method