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.datareader.pagexml.reader import PageXML
  from calamari_ocr.ocr.training.pipeline_params import CalamariSplitTrainerPipelineParams, CalamariTrainOnlyPipelineParams
  from calamari_ocr.scripts.train import main
  from calamari_ocr.test.calamari_test_scenario import CalamariTestScenario
label_desc: Use image node_id 1 for calling the TestPageXMLNoPreload obj's underlying member method code with example usage: obj.tearDown() without return types