code: def testTimeoutFn(self):
      timeout_fn_calls = [0]
  
      def timeout_fn():
          timeout_fn_calls[0] += 1
          return timeout_fn_calls[0] > 3
  
      results = list(
          checkpoint_utils.checkpoints_iterator(
              "/non-existent-dir", timeout=0.1, timeout_fn=timeout_fn
          )
      )
      self.assertEqual([], results)
      self.assertEqual(4, timeout_fn_calls[0])
  
imports: import os
  import pathlib
  import time
  import numpy
  from tensorflow.core.protobuf import config_pb2
  from tensorflow.python.checkpoint import checkpoint
  from tensorflow.python.client import session
  from tensorflow.python.framework import dtypes
  from tensorflow.python.framework import errors_impl
  from tensorflow.python.framework import ops
  from tensorflow.python.framework import test_util
  from tensorflow.python.ops import init_ops
  from tensorflow.python.ops import partitioned_variables
  from tensorflow.python.ops import resource_variable_ops
  from tensorflow.python.ops import variable_scope
  from tensorflow.python.ops import variables
  from tensorflow.python.platform import gfile
  from tensorflow.python.platform import test
  from tensorflow.python.training import checkpoint_utils
  from tensorflow.python.training import saver
label_desc: Use image node_id 5 for calling the CheckpointIteratorTest obj's underlying member method code with example usage: obj.testTimeoutFn() and returns: unknown