code: def test_on_files_no_preload(self):
      cfp = default_cross_fold_params(
          default_files_trainer_params(preload=False)
      )
      with tempfile.TemporaryDirectory() as d:
          cfp.best_models_dir = d
          main(cfp)
  
imports: import os
  import tempfile
  import unittest
  from tensorflow import keras
  from calamari_ocr.ocr.dataset.imageprocessors import AugmentationProcessorParams
  from calamari_ocr.ocr.training.cross_fold_trainer import CrossFoldTrainerParams
  from calamari_ocr.scripts.cross_fold_train import main
  from calamari_ocr.test.test_train_file import uw3_trainer_params
  from calamari_ocr.test.test_train_pagexml import default_trainer_params
label_desc: Use image node_id 6 for calling the TestCrossFoldTrain obj's underlying member method code with example usage: obj.test_on_files_no_preload() without return types