code: def merge_list_members_RIID(self, list_, record_data, merge_rule):
          
          list_ = list_.get_soap_object(self.client)
          result = self.call('mergeListMembersRIID', list_, record_data, merge_rule)
          return RecipientResult(result.recipientResult)
docs: Responsys.mergeListMembersRIID call
  
          Accepts:
              InteractObject list_
              RecordData record_data
              ListMergeRule merge_rule
  
          Returns a RecipientResult