code: def test_multilabel_field_empty_field_works(self):
      vocab = Vocabulary()
      vocab.add_token_to_namespace(
          "label1", namespace="test_empty_labels"
      )
      vocab.add_token_to_namespace(
          "label2", namespace="test_empty_labels"
      )
  
      f = MultiLabelField([], label_namespace="test_empty_labels")
      f.index(vocab)
      tensor = (
          f.as_tensor(f.get_padding_lengths()).detach().cpu().numpy()
      )
      numpy.testing.assert_array_almost_equal(
          tensor, numpy.array([0, 0])
      )
      g = f.empty_field()
      g.index(vocab)
      tensor = (
          g.as_tensor(g.get_padding_lengths()).detach().cpu().numpy()
      )
      numpy.testing.assert_array_almost_equal(
          tensor, numpy.array([0, 0])
      )
  
      h = MultiLabelField(
          [0, 0, 1],
          label_namespace="test_empty_labels",
          num_labels=3,
          skip_indexing=True,
      )
      tensor = h.empty_field().as_tensor(None).detach().cpu().numpy()
      numpy.testing.assert_array_almost_equal(
          tensor, numpy.array([0, 0, 0])
      )
  
imports: import logging
  import numpy
  import pytest
  from allennlp.common.checks import ConfigurationError
  from allennlp.common.testing import AllenNlpTestCase
  from allennlp.data.fields import MultiLabelField
  from allennlp.data.vocabulary import Vocabulary
label_desc: Use image node_id 8 for calling the TestMultiLabelField obj's underlying member method code with example usage: obj.test_multilabel_field_empty_field_works() without return types