code: def test_null_mask_path_missing(self):
      batch = input_batch.InputBatch(
          pa.RecordBatch.from_arrays(
              [pa.array([[1], None, []])], ["feature"]
          )
      )
      path = types.FeaturePath(["feature2"])
      expected_mask = np.array([True, True, True])
      np.testing.assert_array_equal(
          batch.null_mask(path), expected_mask
      )
  
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 2 for calling the InputBatchTest obj's underlying member method code with example usage: obj.test_null_mask_path_missing() without return types