message: Re-create the Checkpoint object in the unit test
diff: @@ -1326,17 +1326,19 @@ class CheckpointingTests(test.TestCase):
  @test_util.run_in_graph_and_eager_modes
  def test_restore_after_adding_empty_checkpointable_data_structure(self):
  - with ops.Graph().as_default(), self.session(graph=ops.get_default_graph()):
  model = NonLayerCheckpointable()
  checkpoint = checkpointable_utils.Checkpoint(model=model)
  checkpoint.restore(None).initialize_or_restore()
  checkpoint_directory = self.get_temp_dir()
  checkpoint_prefix = os.path.join(checkpoint_directory, "ckpt")
  save_path = checkpoint.save(checkpoint_prefix)
  - with ops.Graph().as_default(), self.session(graph=ops.get_default_graph()):
  +
  + del model, checkpoint
  +
  model = NonLayerCheckpointable()
  model.dict = {"a": 1}
  model.list = {"b": 1}
  + checkpoint = checkpointable_utils.Checkpoint(model=model)
  load_status = checkpoint.restore(save_path)
  load_status.assert_existing_objects_matched().run_restore_ops()
  