code: def tearDown(self):
      cuda.runtime.streamDestroy(self.stream_ptr)
  
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 2 for calling the TestExternalStream obj's underlying member method code with example usage: obj.tearDown() without return types