code: def mark_complex(self, name, serializer, deserializer):
          
  
          self._complex_properties[name] = (serializer, deserializer)
docs: Mark a property as complex with serializer and deserializer functions.
  
          Args:
              name (str): The name of the complex property.
              serializer (callable): The function to call to serialize the property's
                  value to something that can be saved in a json.
              deserializer (callable): The function to call to unserialize the property
                  from a dict loaded by a json back to the original value.