code: def testPoolOperation(self):
      reduce_operation = mtf.PoolOperation(
          self.image, [2, 2], [2, 2], "AVG_2D"
      )
      self.assertEqual(
          reduce_operation.splittable_dims, frozenset(["batch", "in"])
      )
      self.assertEqual(
          reduce_operation.unsplittable_dims,
          frozenset(["grid_h", "grid_w"]),
      )
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  from absl.testing import parameterized
  import mesh_tensorflow
  from mesh_tensorflow import test_utils
  import numpy
  import tensorflow.compat.v1
  from tensorflow.python.framework import test_util
label_desc: Use image node_id 8 for calling the OperationSplittabilityTest obj's underlying member method code with example usage: obj.testPoolOperation() without return types