code: def testFunctionInputConstantFoldingCacheMiss(self):
      @polymorphic_function.function
      def add(a, b):
          return a + b
  
      c0 = api.copy_to_mesh(
          constant_op.constant(17.0),
          Layout.replicated(self.mesh, rank=0),
      )
      c1 = api.copy_to_mesh(
          constant_op.constant(21.0),
          Layout.replicated(self.mesh, rank=0),
      )
      c2 = api.copy_to_mesh(
          constant_op.constant(0.0),
          Layout.replicated(self.mesh, rank=0),
      )
  
      stats1 = api._dtensor_device()._get_stats()
      # First call should log a cache miss.
      self.assertAllEqual(add(c0, c1), 38.0)
  
      # Second call should also log a cache miss since second constant changed.
      self.assertAllEqual(add(c0, c2), 17.0)
  
      # Third call should not log a cache miss since the same input as the prev.
      self.assertAllEqual(add(c0, c2), 17.0)
  
      # Fourth call should log a cache miss since first input changed.
      self.assertAllEqual(add(c1, c2), 21.0)
  
      stats2 = api._dtensor_device()._get_stats()
      diff = {key: stats2[key] - stats1[key] for key in stats1.keys()}
      self.assertEqual(diff["function_manager.miss"], 3)
      self.assertEqual(diff["function_manager.hit"], 1)
  
imports: import gc
  import numpy
  from tensorflow.dtensor.python import api
  from tensorflow.dtensor.python import d_variable
  from tensorflow.dtensor.python import layout
  from tensorflow.dtensor.python.tests import test_util
  from tensorflow.python.eager.polymorphic_function import polymorphic_function
  from tensorflow.python.framework import combinations
  from tensorflow.python.framework import constant_op
  from tensorflow.python.framework import dtypes
  from tensorflow.python.ops import array_ops
  from tensorflow.python.ops import gen_stateless_random_ops
  from tensorflow.python.ops import math_ops
  from tensorflow.python.platform import test
label_desc: Use image node_id 4 for calling the DTensorDeviceCacheTest obj's underlying member method code with example usage: obj.testFunctionInputConstantFoldingCacheMiss() and returns: unknown