code: def update(self, defaults=values.unset):
          
          data = values.of({'Defaults': serialize.object(defaults), })
  
          payload = self._version.update(
              'POST',
              self._uri,
              data=data,
          )
  
          return DefaultsInstance(self._version, payload, assistant_sid=self._solution['assistant_sid'], )
docs: Update the DefaultsInstance
  
          :param dict defaults: A JSON string that describes the default task links.
  
          :returns: Updated DefaultsInstance
          :rtype: twilio.rest.autopilot.v1.assistant.defaults.DefaultsInstance