code: def testSleeper_Sleep(self):
      # Burn in.
      for _ in range(10):
          concurrency.Sleeper().sleep(0.01)
  
      def sleep_test_thread(duration):
          start_time = time.time()
          concurrency.Sleeper().sleep(duration)
          self.assertAlmostEqual(
              time.time(), start_time + duration, delta=0.005
          )
  
      threads = [
          threading.Thread(target=sleep_test_thread, args=[i * 0.1])
          for i in range(10)
      ]
      for t in threads:
          t.start()
      for t in threads:
          t.join()
  
file_path: magenta/magenta/common/concurrency_test.py
imports: import threading
  import time
  from magenta.common import concurrency
  import tensorflow.compat.v1
label_desc: Use image node_id 2 for calling the ConcurrencyTest obj's underlying member method code with example usage: obj.testSleeper_Sleep() without return types