docs: def get_assessment_part_item_design_session(self, *args, **kwargs):
          """Gets the ``OsidSession`` associated with the assessment part item design service.
  
          return: (osid.assessment.authoring.AssessmentPartItemDesignSession)
                  - an ``AssessmentPartItemDesignSession``
          raise:  OperationFailed - unable to complete request
          raise:  Unimplemented - ``supports_assessment_part_item_design()`` is
                  ``false``
          *compliance: optional -- This method must be implemented if
          ``supports_assessment_part_lookup()`` is ``true``.*
  
          """
          if not self.supports_assessment_part_lookup():  # This is kludgy, but only until Tom fixes spec
              raise errors.Unimplemented()
          if self._proxy_in_args(*args, **kwargs):
              raise errors.InvalidArgument('A Proxy object was received but not expected.')
          # pylint: disable=no-member
          return sessions.AssessmentPartItemDesignSession(runtime=self._runtime)