code: def test_list_lengths_null_array(self):
      batch = input_batch.InputBatch(
          pa.RecordBatch.from_arrays(
              [
                  pa.array([None, None, None], type=pa.null()),
              ],
              ["f1"],
          )
      )
      np.testing.assert_array_equal(
          batch.list_lengths(types.FeaturePath(["f1"])), [0, 0, 0]
      )
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  from absl.testing import absltest
  import numpy
  import pyarrow
  from tensorflow_data_validation import types
  from tensorflow_data_validation.statistics.generators import input_batch
label_desc: Use image node_id 14 for calling the InputBatchTest obj's underlying member method code with example usage: obj.test_list_lengths_null_array() without return types