old_contents: class ErrorNotification(object):
      def __init__(self, error, text):
          self.error = error
          self.text = text
  
      @classmethod
      def from_mapping(cls, error_mapping):
          return cls(error=error_mapping['error'],
                     text=error_mapping['text'])
  
new_contents: from pywatson.util.map_initializable import MapInitializable
  
  
  class ErrorNotification(MapInitializable):
      def __init__(self, error, text):
          self.error = error
          self.text = text
  
      @classmethod
      def from_mapping(cls, error_mapping):
          return cls(error=error_mapping['error'],
                     text=error_mapping['text'])
  
subject: Make ErrorNotification map-initializable