code: def check_del(self, null, ptds):
      stream = cuda.Stream(null=null, ptds=ptds).use()
      assert stream is cuda.get_current_stream()
      stream_ptr = stream.ptr
      x = from_data.array([1, 2, 3])
      del stream
      assert stream_ptr == cuda.get_current_stream().ptr
      cuda.Stream.null.use()
      assert cuda.Stream.null is cuda.get_current_stream()
      # Want to test cudaStreamDestory is issued, but
      # runtime.streamQuery(stream_ptr) causes SEGV. We cannot test...
      del x
  
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 6 for calling the TestStream obj's underlying member method code with example usage: obj.check_del(null, ptds) without return types