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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_assessment_part_items(self, assessment_part_id):
 """Gets the list of items mapped to the given ``AssessmentPart``. In plenary mode, the returned list contains all known items or an error results. Otherwise, the returned list may contain only those items that are accessible through this session. arg: assessment_part_id (osid.id.Id):
 ``Id`` of the ``AssessmentPart`` return: (osid.assessment.ItemList) - list of items raise: NotFound - ``assessment_part_id`` not found raise: NullArgument - ``assessment_part_id`` is ``null`` raise: OperationFailed - unable to complete request raise: PermissionDenied - authorization failure *compliance: mandatory -- This method is must be implemented.* """

        mgr = self._get_provider_manager('ASSESSMENT_AUTHORING', local=True)
        lookup_session = mgr.get_assessment_part_lookup_session(proxy=self._proxy)
        if self._catalog_view == ISOLATED:
            lookup_session.use_isolated_bank_view()
        else:
            lookup_session.use_federated_bank_view()
        item_ids = lookup_session.get_assessment_part(assessment_part_id).get_item_ids()
        mgr = self._get_provider_manager('ASSESSMENT')
        lookup_session = mgr.get_item_lookup_session(proxy=self._proxy)
        lookup_session.use_federated_bank_view()
        return lookup_session.get_items_by_ids(item_ids)