code: def test_length_diff_generator_both_missing(self):
      batch = input_batch.InputBatch(
          pa.RecordBatch.from_arrays(
              [pa.array([[1], [1], [1]])], ["required"]
          )
      )
      path1 = types.FeaturePath(["f1"])
      path2 = types.FeaturePath(["f2"])
      required_path = types.FeaturePath("required")
      generator = length_diff_generator.LengthDiffGenerator(
          path1, path2, required_paths=[required_path]
      )
      accumulator = generator.create_accumulator()
      accumulator = generator.add_input(accumulator, batch)
      self.assertEqual((0, 0), generator.extract_output(accumulator))
  
file_path: data-validation/tensorflow_data_validation/statistics/generators/constituents/length_diff_generator_test.py
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  from absl.testing import absltest
  import pyarrow
  from tensorflow_data_validation import types
  from tensorflow_data_validation.statistics.generators import input_batch
  from tensorflow_data_validation.statistics.generators.constituents import length_diff_generator
label_desc: Use image node_id 6 for calling the LengthDiffGeneratorTest obj's underlying member method code with example usage: obj.test_length_diff_generator_both_missing() without return types