def get_child_objective_banks(self, objective_bank_id=None):
pass<EOL>
Gets the children of the given objective bank.

        arg:    objectiveBankId (osid.id.Id): the Id to query
        return: (osid.learning.ObjectiveBankList) - the children of the
                objective bank
        raise:  NotFound - objectiveBankId is not found
        raise:  NullArgument - objectiveBankId is null
        raise:  OperationFailed - unable to complete request
        raise:  PermissionDenied - authorization failure
        compliance: mandatory - This method must be implemented.