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

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