code: def test_ignore_nan_true():
      """check result with None in class"""
  
      data = {
          "col": [1, 2, 3, 4, 5, 6] * 100,
          "label": ["a", "a", "a", None, "b", "b"] * 100,
      }
      ds = Dataset(pd.DataFrame(data), label="label")
  
      # Act
      result = ClassImbalance(ignore_nan=True).run(ds)
      expected_result_value = {"a": 0.6, "b": 0.4}
  
      # Assert
      assert_that(result.value, equal_to(expected_result_value))
  
file_path: deepchecks/tests/tabular/checks/integrity/class_imbalance_test.py
imports: import pandas
  from hamcrest import assert_that, calling, equal_to, has_items, has_length, raises
  from deepchecks.core import ConditionCategory
  from deepchecks.core.errors import DeepchecksValueError, ModelValidationError
  from deepchecks.tabular.checks.data_integrity.class_imbalance import ClassImbalance
  from deepchecks.tabular.dataset import Dataset
  from tests.base.utils import equal_condition_result
label_desc: Use image node_id 7 for calling a global function with example usage: test_ignore_nan_true() without return types