code: def test_file(
      self,
      save_final,
      final_filename,
      save_key_metric,
      key_metric_name,
      key_metric_n_saved,
      key_metric_filename,
      key_metric_save_state,
      key_metric_greater_or_equal,
      key_metric_negative_sign,
      epoch_level,
      save_interval,
      n_saved,
      filenames,
      multi_devices=False,
  ):
      data = [0] * 8
  
      # set up engine
      def _train_func(engine, batch):
          engine.state.metrics["val_loss"] = engine.state.iteration
  
      engine = Engine(_train_func)
  
      # set up testing handler
      net = torch.nn.PReLU()
      if multi_devices:
          net = torch.nn.DataParallel(net)
      optimizer = optim.SGD(net.parameters(), lr=0.02)
      with tempfile.TemporaryDirectory() as tempdir:
          handler = CheckpointSaver(
              tempdir,
              {"net": net, "opt": optimizer},
              "CheckpointSaver",
              "test",
              save_final,
              final_filename,
              save_key_metric,
              key_metric_name,
              key_metric_n_saved,
              key_metric_filename,
              key_metric_save_state,
              key_metric_greater_or_equal,
              key_metric_negative_sign,
              epoch_level,
              save_interval,
              n_saved,
          )
          handler.attach(engine)
          engine.run(data, max_epochs=2)
          engine.run(data, max_epochs=5)
          for filename in filenames:
              self.assertTrue(
                  os.path.exists(os.path.join(tempdir, filename))
              )
  
file_path: MONAI/tests/test_handler_checkpoint_saver.py
imports: from __future__ import annotations
  import os
  import tempfile
  import unittest
  import torch
  import torch.optim
  from ignite.engine import Engine
  from parameterized import parameterized
  from monai.handlers import CheckpointLoader, CheckpointSaver
label_desc: Use image node_id 1 for calling the TestHandlerCheckpointSaver obj's underlying member method code with example usage: obj.test_file(save_final, final_filename, save_key_metric, key_metric_name, key_metric_n_saved, key_metric_filename, key_metric_save_state, key_metric_greater_or_equal, key_metric_negative_sign, epoch_level, save_interval, n_saved, filenames, multi_devices) without return types