code: def update(self, instance_id: str, details: UpdateDetails, async_allowed: bool) -> UpdateServiceSpec:
          
          raise NotImplementedError()
docs: Further readings `CF Broker API#Update <https://docs.cloudfoundry.org/services/api.html#updating_service_instance>`_
  
          :param instance_id: Instance id provided by the platform
          :param details: Details about the service to update
          :param async_allowed: Client allows async creation
          :rtype: UpdateServiceSpec
          :raises ErrAsyncRequired: If async is required but not supported