def get_activity_objective_bank_session(self):
raise Unimplemented()<EOL>
Gets the session for retrieving activity to objective bank mappings.

        return: (osid.learning.ActivityObjectiveBankSession) - an
                ``ActivityObjectiveBankSession``
        raise:  OperationFailed - unable to complete request
        raise:  Unimplemented - ``supports_activity_objective_bank()``
                is ``false``
        *compliance: optional -- This method must be implemented if
        ``supports_activity_objective_bank()`` is ``true``.*