(self, instance)
Handles any processing needed for an instance that already exists for
        a recipient that we want to keep.
        The instance is not saved in this method because all instances are saved at the
        end of processing.

        :return: True if the instance should be saved at the end of processing,
        otherwise False
Handles any processing needed for an instance that already exists for
        a recipient that we want to keep.
        The instance is not saved in this method because all instances are saved at the
        end of processing.
Handles any processing needed for an instance that already exists for a recipient that we want to keep . The instance is not saved in this method because all instances are saved at the end of processing .
def handle_existing_instance(self, instance):
        """
        Handles any processing needed for an instance that already exists for
        a recipient that we want to keep.
        The instance is not saved in this method because all instances are saved at the
        end of processing.

        :return: True if the instance should be saved at the end of processing,
        otherwise False
        """
        raise NotImplementedError()
def handle_existing_instance ( self , instance ) : raise NotImplementedError ( )