code: def testSizeAndClear(self):
      with ops.Graph().as_default() as g:
          with ops.device("/cpu:0"):
              x = array_ops.placeholder(dtypes.float32, name="x")
              pi = array_ops.placeholder(dtypes.int64)
              gi = array_ops.placeholder(dtypes.int64)
              v = 2.0 * (array_ops.zeros([128, 128]) + x)
          with ops.device(test.gpu_device_name()):
              stager = data_flow_ops.MapStagingArea(
                  [dtypes.float32, dtypes.float32],
                  shapes=[[], [128, 128]],
                  names=["x", "v"],
              )
              stage = stager.put(pi, {"x": x, "v": v})
              size = stager.size()
              clear = stager.clear()
  
      g.finalize()
  
      with self.session(graph=g) as sess:
          sess.run(stage, feed_dict={x: -1, pi: 3})
          self.assertEqual(sess.run(size), 1)
          sess.run(stage, feed_dict={x: -1, pi: 1})
          self.assertEqual(sess.run(size), 2)
          sess.run(clear)
          self.assertEqual(sess.run(size), 0)
  
imports: import queue
  import threading
  import numpy
  from tensorflow.python.framework import constant_op
  from tensorflow.python.framework import dtypes
  from tensorflow.python.framework import errors
  from tensorflow.python.framework import ops
  from tensorflow.python.framework import test_util
  from tensorflow.python.ops import array_ops
  from tensorflow.python.ops import data_flow_ops
  from tensorflow.python.ops import math_ops
  from tensorflow.python.platform import test
label_desc: Use image node_id 6 for calling the MapStageTest obj's underlying member method code with example usage: obj.testSizeAndClear() without return types