code: def ensemble(self):
      ensemble_data = list()
      final_rui = {}
      final_dev = {}
  
      for r in self.recommenders:
          for conf_sample in self.rec_conf[r]:
              user, item, rui, conf = conf_sample
              if final_rui.get(user, -1) == -1:
                  final_rui.setdefault(user, {}).update({item: rui})
                  final_dev.setdefault(user, {}).update({item: conf})
              else:
                  if final_rui[user].get(item, -1) == -1:
                      final_rui[user][item] = (
                          final_rui[user].get(item, 0) + rui
                      )
                      final_dev[user][item] = (
                          final_dev[user].get(item, 0) + conf
                      )
                  else:
                      if conf > final_dev[user][item]:
                          final_dev[user][item] = conf
                          final_rui[user][item] = rui
  
      for user in final_rui:
          for item in final_rui[user]:
              rui = final_rui[user][item]
  
              if rui > self.train_set["max_value"]:
                  rui = self.train_set["max_value"]
              elif rui < self.train_set["min_value"]:
                  rui = self.train_set["min_value"]
  
              ensemble_data.append((user, item, rui))
  
      self.update_file(ensemble_data, self.ensemble_file)
  
imports: from multiprocessing.pool import Pool
  from random import shuffle
  import numpy
  import os
  from caserec.recommenders.rating_prediction.itemknn import ItemKNN
  from caserec.recommenders.rating_prediction.matrixfactorization import MatrixFactorization
  from caserec.recommenders.rating_prediction.svdplusplus import SVDPlusPlus
  from caserec.recommenders.rating_prediction.userknn import UserKNN
  from caserec.utils.process_data import ReadFile
  from caserec.utils.extra_functions import ComputeBui
label_desc: Use image node_id 11 for calling the ECoRec obj's underlying member method code with example usage: obj.ensemble() without return types