code: def test_get_text_field_mask_returns_a_correct_mask_list_field(self):
      text_field_tensors = {
          "list_tokens": torch.LongTensor(
              [
                  [[1, 2], [3, 0], [2, 0], [0, 0], [0, 0]],
                  [[5, 0], [4, 6], [0, 0], [0, 0], [0, 0]],
              ]
          )
      }
      actual_mask = util.get_text_field_mask(
          text_field_tensors, num_wrapping_dims=1
      ).numpy()
      expected_mask = (
          text_field_tensors["list_tokens"].numpy() > 0
      ).astype("int32")
      assert_almost_equal(actual_mask, expected_mask)
  
imports: from __future__ import with_statement
  from __future__ import division
  from __future__ import absolute_import
  import numpy
  from numpy.testing import assert_array_almost_equal, assert_almost_equal
  import torch
  import pytest
  from allennlp.common.checks import ConfigurationError
  from allennlp.common.testing import AllenNlpTestCase
  from allennlp.nn import util
label_desc: Use image node_id 13 for calling the TestNnUtil obj's underlying member method code with example usage: obj.test_get_text_field_mask_returns_a_correct_mask_list_field() without return types