code: def tearDown(self) -> None:
      keras.backend.clear_session()
  
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 1 for calling the TestCrossFoldTrain obj's underlying member method code with example usage: obj.tearDown() without return types