import tensorflow as tf

      # Create a saver that will keep the last 2 checkpoints plus one every 0.7
      # seconds.
      start_time = time.time()
      save = tf.train.Saver({"v": v}, max_to_keep=2,
                            keep_checkpoint_every_n_hours=0.7 / 3600)
      self.assertEqual([], save.last_checkpoints)
