code: def test_classlabel_int2str():
      names = ["negative", "positive"]
      classlabel = ClassLabel(names=names)
      for i in range(len(names)):
          assert classlabel.int2str(i) == names[i]
      with pytest.raises(ValueError):
          classlabel.int2str(len(names))
      with pytest.raises(ValueError):
          classlabel.int2str(-1)
      with pytest.raises(ValueError):
          classlabel.int2str(None)
  
imports: import datetime
  from unittest import TestCase
  from unittest.mock import patch
  import numpy
  import pandas
  import pyarrow
  import pytest
  from datasets import Array2D
  from datasets.arrow_dataset import Dataset
  from datasets.features import Audio, ClassLabel, Features, Image, Sequence, Value
  from datasets.features.features import _arrow_to_datasets_dtype, _cast_to_python_objects, cast_to_python_objects, encode_nested_example, generate_from_dict, string_to_arrow
  from datasets.features.translation import Translation, TranslationVariableLanguages
  from datasets.info import DatasetInfo
  from datasets.utils.py_utils import asdict
  from ..utils import require_jax, require_tf, require_torch
label_desc: Use image node_id 3 for calling a global function with example usage: test_classlabel_int2str() without return types