code: def test_optimize_cache_multi_gpus(self):
      if (
          _accelerator.ACCELERATOR_CUB
          in _accelerator.get_reduction_accelerators()
      ):
          pytest.skip("optimize cannot be mocked for CUB reduction")
  
      target = cupyx.optimizing._optimize._optimize
      target_full_name = "{}.{}".format(
          target.__module__, target.__name__
      )
  
      with mock.patch(target_full_name) as optimize_impl:
          my_sum = cupy.ReductionKernel(
              "T x", "T out", "x", "a + b", "out = a", "0", "my_sum"
          )
  
          with cupyx.optimizing.optimize():
              with cupy.cuda.Device(0):
                  x = testing.shaped_arange((3, 4), cupy)
                  my_sum(x, axis=1)
                  assert optimize_impl.call_count == 1
  
              with cupy.cuda.Device(1):
                  x = testing.shaped_arange((3, 4), cupy)
                  my_sum(x, axis=1)
                  assert optimize_impl.call_count == 2
  
imports: import os
  import tempfile
  import unittest
  from unittest import mock
  import pytest
  import cupy
  from cupy import testing
  from cupy._core import _accelerator
label_desc: Use image node_id 4 for calling the TestOptimize obj's underlying member method code with example usage: obj.test_optimize_cache_multi_gpus() without return types