docstr: Method to initialize recommender algorithm.
docstr_tok: ["Method","to","initialize","recommender","algorithm","."]
code: def read_files(self):
      """
      Method to initialize recommender algorithm.
  
      """
  
      self.n_files = len(self.train_files)
  
      self.users = []
      self.items = []
  
      for train_file in self.train_files:
          train_set = ReadFile(
              train_file, sep=self.sep, as_binary=self.as_binary
          ).read()
          self.users += train_set["users"]
          self.items += train_set["items"]
          self.train_set_list.append(train_set)
          self.dir_name = os.path.dirname(train_file)
  
      self.users = set(self.users)
      self.items = set(self.items)
  
      if self.test_file is not None:
          self.test_set = ReadFile(self.test_file).read()
          self.users = sorted(
              set(list(self.users) + list(self.test_set["users"]))
          )
          self.items = sorted(
              set(list(self.items) + list(self.test_set["items"]))
          )
  
      for i, item in enumerate(self.items):
          self.item_to_item_id.update({item: i})
          self.item_id_to_item.update({i: item})
      for u, user in enumerate(self.users):
          self.user_to_user_id.update({user: u})
          self.user_id_to_user.update({u: user})
  
imports: from scipy.spatial.distance import squareform, pdist
  import numpy
  import os
  from caserec.clustering.kmedoids import kmedoids
  from caserec.recommenders.item_recommendation.base_item_recommendation import BaseItemRecommendation
  from caserec.recommenders.item_recommendation.itemknn import ItemKNN
  from caserec.recommenders.item_recommendation.most_popular import MostPopular
  from caserec.recommenders.item_recommendation.userknn import UserKNN
  from caserec.utils.process_data import ReadFile, WriteFile
  from caserec.recommenders.item_recommendation.bprmf import BprMF
label_desc: Use image node_id 2 for calling the GroupBasedRecommender obj's underlying member method code with example usage: obj.read_files() without return types