code: def tearDown(self):
      if self.old_pool is not None:
          cuda.set_allocator(self.old_pool.malloc)
  
imports: import unittest
  import pytest
  import cupy
  from cupy import cuda
  from cupy import testing
label_desc: Use image node_id 2 for calling the TestNewDLPackConversion obj's underlying member method code with example usage: obj.tearDown() without return types