code: def register_for_deleted_asset(self, asset_id):
          
          # Implemented from template for
          # osid.resource.ResourceNotificationSession.register_for_deleted_resource
          if not MONGO_LISTENER.receivers[self._ns][self._receiver]['d']:
              MONGO_LISTENER.receivers[self._ns][self._receiver]['d'] = []
          if isinstance(MONGO_LISTENER.receivers[self._ns][self._receiver]['d'], list):
              MONGO_LISTENER.receivers[self._ns][self._receiver]['d'].append(asset_id.get_identifier())
docs: Registers for notification of a deleted asset.
  
          ``AssetReceiver.deletedAssets()`` is invoked when the specified
          asset is deleted or removed from this repository.
  
          arg:    asset_id (osid.id.Id): the ``Id`` of the ``Asset`` to
                  monitor
          raise:  NullArgument - ``asset_id`` is ``null``
          raise:  OperationFailed - unable to complete request
          raise:  PermissionDenied - authorization failure
          *compliance: mandatory -- This method must be implemented.*