code: def testMemoryLimit(self):
      memory_limit = 512 * 1024  # 512K
      chunk = 200 * 1024  # 256K
      capacity = memory_limit // chunk
  
      with ops.Graph().as_default() as g:
          with ops.device("/cpu:0"):
              x = array_ops.placeholder(dtypes.uint8, name="x")
              pi = array_ops.placeholder(dtypes.int64, name="pi")
              gi = array_ops.placeholder(dtypes.int64, name="gi")
          with ops.device(test.gpu_device_name()):
              stager = data_flow_ops.MapStagingArea(
                  [dtypes.uint8], memory_limit=memory_limit, shapes=[[]]
              )
              stage = stager.put(pi, [x], [0])
              get = stager.get()
              size = stager.size()
  
      g.finalize()
  
      value_queue = queue.Queue()
      n = 8
  
      with self.session(graph=g) as sess:
          # Stage data in a separate thread which will block when it hits the
          # staging area's capacity and thus not fill the value_queue with n tokens
          def thread_run():
              for i in range(n):
                  data = np.full(chunk, i, dtype=np.uint8)
                  sess.run(stage, feed_dict={x: data, pi: i})
                  value_queue.put(0)
  
          t = threading.Thread(target=thread_run)
          t.daemon = True
          t.start()
  
          # Get tokens from the value_queue until a timeout occurs
          try:
              for i in range(n):
                  value_queue.get(timeout=TIMEOUT)
          except queue.Empty:
              pass
  
          # Should've timed out on the iteration 'capacity'
          if not i == capacity:
              self.fail(
                  "Expected to timeout on iteration '{}' "
                  "but instead timed out on iteration '{}' "
                  "Staging Area size is '{}' and configured "
                  "capacity is '{}'.".format(
                      capacity, i, sess.run(size), capacity
                  )
              )
  
          # Should have capacity elements in the staging area
          self.assertEqual(sess.run(size), capacity)
  
          # Clear the staging area completely
          for i in range(n):
              sess.run(get)
  
          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 8 for calling the MapStageTest obj's underlying member method code with example usage: obj.testMemoryLimit() without return types