code: def get_movielens_data():
      
  
      train_data, test_data = _get_raw_movielens_data()
  
      uids = set()
      iids = set()
  
      for uid, iid, rating, timestamp in itertools.chain(_parse(train_data),
                                                         _parse(test_data)):
          uids.add(uid)
          iids.add(iid)
  
      rows = max(uids) + 1
      cols = max(iids) + 1
  
      return (_build_interaction_matrix(rows, cols, _parse(train_data)),
              _build_interaction_matrix(rows, cols, _parse(test_data)))
docs: Return (train_interactions, test_interactions).