code: def test_count_vocab_items_correctly_indexes_tags(self):
      tags = ["B", "I", "O", "O", "O"]
      sequence_label_field = SequenceLabelField(
          tags, self.text, label_namespace="labels"
      )
  
      counter = defaultdict(lambda: defaultdict(int))
      sequence_label_field.count_vocab_items(counter)
  
      assert counter["labels"]["B"] == 1
      assert counter["labels"]["I"] == 1
      assert counter["labels"]["O"] == 3
      assert set(counter.keys()) == {"labels"}
  
imports: from collections import defaultdict
  import logging
  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 3 for calling the TestSequenceLabelField obj's underlying member method code with example usage: obj.test_count_vocab_items_correctly_indexes_tags() without return types