code: def testDeletion(self):
      checkpoint = util.Checkpoint()
      manager = checkpoint_management.CheckpointManager(
          checkpoint, self.get_temp_dir(), max_to_keep=3
      )
      first_path = manager.save()
      second_path = manager.save()
      third_path = manager.save()
      fourth_path = manager.save()
      self.assertTrue(
          checkpoint_management.checkpoint_exists(fourth_path)
      )
      self.assertTrue(
          checkpoint_management.checkpoint_exists(third_path)
      )
      self.assertTrue(
          checkpoint_management.checkpoint_exists(second_path)
      )
      self.assertFalse(
          checkpoint_management.checkpoint_exists(first_path)
      )
  
imports: import contextlib
  import os
  import pathlib
  import shutil
  import tempfile
  from google.protobuf import text_format
  from tensorflow.core.protobuf import saver_pb2
  from tensorflow.python.checkpoint import checkpoint
  from tensorflow.python.checkpoint import checkpoint_management
  from tensorflow.python.eager import context
  from tensorflow.python.framework import dtypes
  from tensorflow.python.framework import ops
  from tensorflow.python.framework import test_util
  from tensorflow.python.lib.io import file_io
  from tensorflow.python.ops import variables
  from tensorflow.python.platform import gfile
  from tensorflow.python.platform import test
  from tensorflow.python.platform import tf_logging
  from tensorflow.python.training import saver
  from tensorflow.python.training.checkpoint_state_pb2 import CheckpointState
label_desc: Use image node_id 1 for calling the CheckpointManagerTest obj's underlying member method code with example usage: obj.testDeletion() without return types