code: def dataset_ncf_files_empty(data_paths, dataset_ncf_files):
      train_path, test_path, leave_one_out_test_path = data_paths
      train, test, leave_one_out_test = dataset_ncf_files
      train = train[0:0]
      test = test[0:0]
      leave_one_out_test = leave_one_out_test[0:0]
      train.to_csv(train_path, index=False)
      test.to_csv(test_path, index=False)
      leave_one_out_test.to_csv(leave_one_out_test_path, index=False)
      return train_path, test_path, leave_one_out_test_path
  
imports: import calendar
  import datetime
  import os
  from pathlib import Path
  from tempfile import TemporaryDirectory
  import numpy
  import pandas
  import pytest
  from sklearn.model_selection import train_test_split
  from recommenders.utils.constants import DEFAULT_USER_COL, DEFAULT_ITEM_COL, DEFAULT_RATING_COL, DEFAULT_TIMESTAMP_COL
  from recommenders.datasets.python_splitters import numpy_stratified_split
  from recommenders.datasets.python_splitters import python_chrono_split
  from recommenders.utils.spark_utils import start_or_get_spark
label_desc: Use image node_id 21 for calling a global function with example usage: dataset_ncf_files_empty(data_paths, dataset_ncf_files) and returns: train_path,  test_path,  leave_one_out_test_path