code: def test_preprocessing_dtype(self):
      super(VarianceThresholdTest, self)._test_preprocessing_dtype(
          VarianceThreshold, add_NaNs=False
      )
  
file_path: auto-sklearn/test/test_pipeline/components/data_preprocessing/test_variance_threshold.py
imports: from scipy import sparse
  from autosklearn.pipeline.components.data_preprocessing.variance_threshold.variance_threshold import VarianceThreshold
  from autosklearn.pipeline.util import PreprocessingTestCase, _test_preprocessing
label_desc: Use image node_id 3 for calling the VarianceThresholdTest obj's underlying member method code with example usage: obj.test_preprocessing_dtype() without return types