old_contents: from collections import namedtuple
  
  
  class _Sentinel(object):
      """Act as sentinel object
      """
  
  
  undefined = _Sentinel()
  
  
  class http_response(object):
      Mode = namedtuple('Mode', 'BINARY TEXT')('binary', 'text')
  
      MAPPINGS = {'status_code': 'statusCode',
                  'mode': '_mode'}
  
      __slots__ = ['status_code', 'headers', 'body', 'mode']
  
      def __init__(self, status_code, headers=undefined,
                   body=undefined, mode=undefined):
          self.status_code = status_code
          self.headers = headers
          self.body = body
          self.mode = mode
  
      @property
      def json(self):
          result = {}
          for field in self.__slots__:
              value = getattr(self, field)
              if value is not undefined:
                  json_field = self.MAPPINGS.get(field, field)
                  result[json_field] = value
          return result
  
  
  class tcp_response(object):
      def __init__(self, data):
          self.data = data
  
      @property
      def json(self):
          return {'data': self.data}
  
  
  class ResponseBuilder(object):
      def __init__(self, responses, stub_builder):
          self._responses = responses
          self._stub_builder = stub_builder
  
      def is_(self, *responses):
          self._responses.extend(
              [{'is': response.json} for response in responses])
          return self._stub_builder
  
      def proxy(self, response):
          raise NotImplementedError()
  
new_contents: from collections import namedtuple
  
  
  undefined = type('_Sentinel', (object,), {})
  
  
  class http_response(object):
      Mode = namedtuple('Mode', 'BINARY TEXT')('binary', 'text')
  
      MAPPINGS = {'status_code': 'statusCode',
                  'mode': '_mode'}
  
      __slots__ = ['status_code', 'headers', 'body', 'mode']
  
      def __init__(self, status_code, headers=undefined,
                   body=undefined, mode=undefined):
          self.status_code = status_code
          self.headers = headers
          self.body = body
          self.mode = mode
  
      @property
      def json(self):
          result = {}
          for field in self.__slots__:
              value = getattr(self, field)
              if value is not undefined:
                  json_field = self.MAPPINGS.get(field, field)
                  result[json_field] = value
          return result
  
  
  class tcp_response(object):
      def __init__(self, data):
          self.data = data
  
      @property
      def json(self):
          return {'data': self.data}
  
  
  class ResponseBuilder(object):
      def __init__(self, responses, stub_builder):
          self._responses = responses
          self._stub_builder = stub_builder
  
      def is_(self, *responses):
          self._responses.extend(
              [{'is': response.json} for response in responses])
          return self._stub_builder
  
      def proxy(self, response):
          raise NotImplementedError()
  
subject: Create Sentinel type adhoc