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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def get_objectives_by_objective_banks(self, objective_bank_ids):
 """Gets the list of ``Objectives`` corresponding to a list of ``ObjectiveBanks``. arg: objective_bank_ids (osid.id.IdList):
 list of objective bank ``Ids`` return: (osid.learning.ObjectiveList) - list of objectives raise: NullArgument - ``objective_bank_ids`` is ``null`` raise: OperationFailed - unable to complete request raise: PermissionDenied - authorization failure *compliance: mandatory -- This method must be implemented.* """

        # Implemented from template for
        # osid.resource.ResourceBinSession.get_resources_by_bins
        objective_list = []
        for objective_bank_id in objective_bank_ids:
            objective_list += list(
                self.get_objectives_by_objective_bank(objective_bank_id))
        return objects.ObjectiveList(objective_list)