code: def testReturnsSingleCheckpointIfOneShardedCheckpoint(self):
      checkpoint_dir = os.path.join(
          self.get_temp_dir(), "one_checkpoint_found_sharded"
      )
      if not gfile.Exists(checkpoint_dir):
          gfile.MakeDirs(checkpoint_dir)
  
      global_step = variables.Variable(0, name="v0")
  
      # This will result in 3 different checkpoint shard files.
      with ops.device("/cpu:0"):
          variables.Variable(10, name="v1")
      with ops.device("/cpu:1"):
          variables.Variable(20, name="v2")
  
      saver = saver_lib.Saver(sharded=True)
  
      with session_lib.Session(
          target="",
          config=config_pb2.ConfigProto(device_count={"CPU": 2}),
      ) as session:
          session.run(variables.global_variables_initializer())
          save_path = os.path.join(checkpoint_dir, "model.ckpt")
          saver.save(session, save_path, global_step=global_step)
  
      num_found = 0
      for _ in checkpoint_utils.checkpoints_iterator(
          checkpoint_dir, timeout=0
      ):
          num_found += 1
      self.assertEqual(num_found, 1)
  
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 4 for calling the CheckpointIteratorTest obj's underlying member method code with example usage: obj.testReturnsSingleCheckpointIfOneShardedCheckpoint() without return types