@abc.abstractmethod<EOL><INDENT>def get_objective_objective_bank_session(self):<DEDENT>
return<EOL>
Gets the session for retrieving objective to objective bank mappings.

        :return: an ``ObjectiveObjectiveBankSession``
        :rtype: ``osid.learning.ObjectiveObjectiveBankSession``
        :raise: ``OperationFailed`` -- unable to complete request
        :raise: ``Unimplemented`` -- ``supports_objective_objective_bank()`` is ``false``

        *compliance: optional -- This method must be implemented if
        ``supports_objective_objective_bank()`` is ``true``.*