code: def test_with_statement(self):
      stream1 = cuda.Stream()
      stream2 = cuda.Stream()
      assert self.stream == cuda.get_current_stream()
      with stream1:
          assert stream1 == cuda.get_current_stream()
          with stream2:
              assert stream2 == cuda.get_current_stream()
          assert stream1 == cuda.get_current_stream()
      # self.stream is "forgotten"!
      assert cuda.Stream.null == cuda.get_current_stream()
  
imports: import gc
  import threading
  import unittest
  import pytest
  import cupy
  from cupy._creation import from_data
  from cupy import cuda
  from cupy import testing
label_desc: Use image node_id 11 for calling the TestStream obj's underlying member method code with example usage: obj.test_with_statement() without return types