code: def test_simple_train_preload(self):
      trainer_params = setup_trainer_params(preload=True)
      with tempfile.TemporaryDirectory() as d:
          trainer_params.output_dir = d
          main(trainer_params)
  
file_path: calamari/calamari_ocr/test/test_train_ensemble.py
imports: import os
  import tempfile
  import unittest
  from tensorflow import keras
  from tfaip.util.tfaipargparse import post_init
  from calamari_ocr.ocr.dataset.datareader.file import FileDataParams
  from calamari_ocr.ocr.scenario import CalamariEnsembleScenario
  from calamari_ocr.scripts.train import main
  from calamari_ocr.test.calamari_test_scenario import CalamariTestEnsembleScenario
  from calamari_ocr.utils import glob_all
label_desc: Use image node_id 2 for calling the TestTrainFile obj's underlying member method code with example usage: obj.test_simple_train_preload() without return types