code: def testNestedDefaultPaddedShapes(self):
      def fill_tuple(x):
          return (x, array_ops.fill([x], x))
  
      dataset = (
          dataset_ops.Dataset.from_tensor_slices([1, 2, 3, 4])
          .map(fill_tuple)
          .padded_batch(batch_size=2)
      )
      self.assertDatasetProduces(
          dataset,
          expected_output=[
              ([1, 2], [[1, 0], [2, 2]]),
              ([3, 4], [[3, 3, 3, 0], [4, 4, 4, 4]]),
          ],
      )
  
imports: from absl.testing import parameterized
  import numpy
  from tensorflow.python.data.kernel_tests import checkpoint_test_base
  from tensorflow.python.data.kernel_tests import test_base
  from tensorflow.python.data.ops import dataset_ops
  from tensorflow.python.data.ops import options
  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 sparse_tensor
  from tensorflow.python.framework import tensor_shape
  from tensorflow.python.ops import array_ops
  from tensorflow.python.ops import math_ops
  from tensorflow.python.ops import string_ops
  from tensorflow.python.ops.ragged import ragged_tensor_value
  from tensorflow.python.platform import test
  from tensorflow.python.util import compat
label_desc: Use image node_id 8 for calling the PaddedBatchTest obj's underlying member method code with example usage: obj.testNestedDefaultPaddedShapes() and returns: x,  array_ops