code: def testCustomCheckpointPrefix(self):
      directory = self.get_temp_dir()
      checkpoint = util.Checkpoint()
      manager = checkpoint_management.CheckpointManager(
          checkpoint,
          directory,
          max_to_keep=2,
          checkpoint_name="ckpt_name",
      )
      path = manager.save(checkpoint_number=5)
      self.assertEqual(os.path.basename(path), "ckpt_name-5")
      manager = checkpoint_management.CheckpointManager(
          checkpoint, directory, max_to_keep=2
      )
      path = manager.save(checkpoint_number=5)
      self.assertEqual(os.path.basename(path), "ckpt-5")
  
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 7 for calling the CheckpointManagerTest obj's underlying member method code with example usage: obj.testCustomCheckpointPrefix() without return types