code: def test_device_synchronize(self):
      # Tests that a device synchronization does correctly cause all streams
      # to synchronize with each other.
  
      iterations = 10
      for i in range(1, iterations):
          self.assert_good_kernel_launch(
              stream_id(i), read_write=[tensor_id(i)]
          )
  
      self.handler._handle_device_synchronization()
      self.assert_good_kernel_launch(
          stream_id(0),
          read_write=[tensor_id(i) for i in range(1, iterations)],
      )
  
imports: import sys
  import textwrap
  import traceback
  from typing import List
  import torch
  import torch.cuda._sanitizer
  from torch.cuda._sanitizer import StreamId, DataPtr, EventId
  from torch.testing._internal.common_utils import TestCase, run_tests, NoTest, TEST_CUDA
label_desc: Use image node_id 20 for calling the TestEventHandler obj's underlying member method code with example usage: obj.test_device_synchronize() without return types