code: def testSparse(self):
      def reduce_fn(_, value):
          return value
  
      def make_sparse_fn(i):
          return sparse_tensor.SparseTensorValue(
              indices=np.array([[0, 0]]),
              values=(i * np.array([1])),
              dense_shape=np.array([1, 1]),
          )
  
      for i in range(10):
          ds = dataset_ops.Dataset.from_tensors(make_sparse_fn(i + 1))
          result = ds.reduce(make_sparse_fn(0), reduce_fn)
          self.assertValuesEqual(
              make_sparse_fn(i + 1), self.evaluate(result)
          )
  
imports: import time
  from absl.testing import parameterized
  import numpy
  from tensorflow.python.data.experimental.ops import testing
  from tensorflow.python.data.kernel_tests import test_base
  from tensorflow.python.data.ops import dataset_ops
  from tensorflow.python.eager import def_function
  from tensorflow.python.framework import combinations
  from tensorflow.python.framework import constant_op
  from tensorflow.python.framework import dtypes
  from tensorflow.python.framework import errors
  from tensorflow.python.framework import ops
  from tensorflow.python.framework import sparse_tensor
  from tensorflow.python.framework import test_util
  from tensorflow.python.ops import array_ops
  from tensorflow.python.ops import math_ops
  from tensorflow.python.ops import variables
  from tensorflow.python.platform import test
label_desc: Use image node_id 5 for calling the ReduceTest obj's underlying member method code with example usage: obj.testSparse() and returns: value, sparse_tensor