code: def test_class_variables_for_namespace_warnings_work_correctly(self):
      # pylint: disable=protected-access
      tags = ["B", "I", "O", "O", "O"]
      assert "text" not in SequenceLabelField._already_warned_namespaces
      with self.assertLogs(
          logger="allennlp.data.fields.sequence_label_field",
          level="WARNING",
      ):
          _ = SequenceLabelField(
              tags, self.text, label_namespace="text"
          )
  
      # We've warned once, so we should have set the class variable to False.
      assert "text" in SequenceLabelField._already_warned_namespaces
      with pytest.raises(AssertionError):
          with self.assertLogs(
              logger="allennlp.data.fields.sequence_label_field",
              level="WARNING",
          ):
              _ = SequenceLabelField(
                  tags, self.text, label_namespace="text"
              )
  
      # ... but a new namespace should still log a warning.
      assert (
          "text2" not in SequenceLabelField._already_warned_namespaces
      )
      with self.assertLogs(
          logger="allennlp.data.fields.sequence_label_field",
          level="WARNING",
      ):
          _ = SequenceLabelField(
              tags, self.text, label_namespace="text2"
          )
  
imports: from __future__ import with_statement
  from __future__ import absolute_import
  from __future__ import print_function
  from collections import defaultdict
  import pytest
  import numpy
  from allennlp.common.checks import ConfigurationError
  from allennlp.common.testing import AllenNlpTestCase
  from allennlp.data import Token, Vocabulary
  from allennlp.data.fields import TextField, SequenceLabelField
  from allennlp.data.token_indexers import SingleIdTokenIndexer
label_desc: Use image node_id 7 for calling the TestSequenceLabelField obj's underlying member method code with example usage: obj.test_class_variables_for_namespace_warnings_work_correctly() without return types