code: def testNoGraphPollution(self):
      graph = ops.Graph()
      with graph.as_default(), session.Session():
          directory = self.get_temp_dir()
          prefix = os.path.join(directory, "ckpt")
          save_state = _NumpyState()
          saver = util.Checkpoint(numpy=save_state)
          save_state.a = numpy.ones([2, 2])
          save_path = saver.save(prefix)
          saver.restore(save_path)
          graph.finalize()
          saver.save(prefix)
          save_state.a = numpy.zeros([2, 2])
          saver.save(prefix)
          saver.restore(save_path)
  
imports: import io
  import os
  import numpy
  from tensorflow.python.checkpoint import checkpoint
  from tensorflow.python.client import session
  from tensorflow.python.framework import ops
  from tensorflow.python.framework import test_util
  from tensorflow.python.module import module
  from tensorflow.python.platform import test
  from tensorflow.python.trackable import python_state
label_desc: Use image node_id 3 for calling the NumpyStateTests obj's underlying member method code with example usage: obj.testNoGraphPollution() without return types