@@ -9,7 +9,7 @@
 from cuda.core.experimental._stream import Stream
 from cuda.core.experimental._utils.clear_error_support import assert_type
 from cuda.core.experimental._utils.cuda_utils import (
-    _reduce_tuple,
+    _reduce_3_tuple,
     check_or_create_options,
     driver,
     get_binding_version,
@@ -95,9 +95,9 @@ def _check_cooperative_launch(kernel: Kernel, config: LaunchConfig, stream: Stre
     dev = stream.device
     num_sm = dev.properties.multiprocessor_count
     max_grid_size = (
-        kernel.occupancy.max_active_blocks_per_multiprocessor(_reduce_tuple(config.block), config.shmem_size) * num_sm
+        kernel.occupancy.max_active_blocks_per_multiprocessor(_reduce_3_tuple(config.block), config.shmem_size) * num_sm
     )
-    if _reduce_tuple(config.grid) > max_grid_size:
+    if _reduce_3_tuple(config.grid) > max_grid_size:
         # For now let's try not to be smart and adjust the grid size behind users' back.
         # We explicitly ask users to adjust.
         x, y, z = config.grid
 
@@ -48,8 +48,8 @@ def cast_to_3_tuple(label, cfg):
     return cfg + (1,) * (3 - len(cfg))
 
 
-def _reduce_tuple(t: tuple):
-    return functools.reduce(lambda x, y: x * y, t, 1)
+def _reduce_3_tuple(t: tuple):
+    return t[0] * t[1] * t[2]
 
 
 def _check_driver_error(error):
 
@@ -7,14 +7,12 @@
 
 import numpy as np
 import pytest
-from conftest import skipif_testing_with_compute_sanitizer
+from conftest import skipif_need_cuda_headers, skipif_testing_with_compute_sanitizer
 
 import cuda.core.experimental
 from cuda.core.experimental import Device, EventOptions, LaunchConfig, Program, ProgramOptions, launch
 from cuda.core.experimental._memory import _DefaultPinnedMemorySource
 
-from conftest import skipif_need_cuda_headers
-
 
 def test_event_init_disabled():
     with pytest.raises(RuntimeError, match=r"^Event objects cannot be instantiated directly\."):
 
@@ -7,12 +7,11 @@
 
 import numpy as np
 import pytest
+from conftest import skipif_need_cuda_headers
 
 from cuda.core.experimental import Device, LaunchConfig, Program, ProgramOptions, launch
 from cuda.core.experimental._memory import _DefaultPinnedMemorySource
 
-from conftest import skipif_need_cuda_headers
-
 
 def test_launch_config_init(init_cuda):
     config = LaunchConfig(grid=(1, 1, 1), block=(1, 1, 1), shmem_size=0)