code: def test_col_less_than_two_unique_values(
      self, singular_valued_col_data
  ):
      col_of_interest = "col1"
      target_feature = "target"
      pos_label = 1
  
      warn_text = (
          f"Column '{col_of_interest}' has less than 2 unique"
          " values, so feature balance measures for"
          f" {target_feature}=={pos_label} are not being computed"
          " for this column."
      )
      with pytest.warns(UserWarning, match=warn_text):
          FeatureBalanceMeasures(
              cols_of_interest=[col_of_interest],
              label_col=target_feature,
              pos_label=pos_label,
          ).measures(singular_valued_col_data)
  
file_path: responsible-ai-toolbox/responsibleai/tests/databalanceanalysis/test_feature_balance_measures.py
imports: import pandas
  import pytest
  from responsibleai.databalanceanalysis import FeatureBalanceMeasures
  from ..common_utils import assert_series_and_dict_equal
  from .conftest import SYNTHETIC_DATA_GENDER, SYNTHETIC_DATA_LABEL
label_desc: Use image node_id 3 for calling the TestFeatureBalanceMeasures obj's underlying member method code with example usage: obj.test_col_less_than_two_unique_values(singular_valued_col_data) without return types