@abc.abstractmethod<EOL><INDENT>def register_for_deleted_gradebook_columns(self):<DEDENT>
pass<EOL>
Registers for notification of deleted gradebook columns.

        ``GradebookColumnReceiver.deletedGradebookColumns()`` is invoked
        when a gradebook column is removed from this gradebook.

        :raise: ``OperationFailed`` -- unable to complete request
        :raise: ``PermissionDenied`` -- authorization failure

        *compliance: mandatory -- This method must be implemented.*