old_contents: class WatsonAnswer(object):
      """An answer received from Watson"""
  
      def __init__(self, answer_mapping):
          """Create a Watson Answer from the given mapping.
  
          :param answer_mapping: the Mapping representing a response from Watson
          :type answer_mapping: Mapping
          :return: Answer
          """
          pass
  
new_contents: class WatsonAnswer(object):
      """An answer received from Watson"""
  
      def __init__(self, answer_mapping):
          """Create a Watson Answer from the given mapping.
  
          :param answer_mapping: the Mapping representing a response from Watson
          :type answer_mapping: Mapping
          :return: Answer
          """
          self.answer_mapping = answer_mapping
  
subject: Add dummy instance variable