code: def test_preprocessing_dtype(self):
      super(DensifierComponentTest, self)._test_preprocessing_dtype(
          Densifier
      )
  
imports: import numpy
  from autosklearn.pipeline.components.feature_preprocessing.densifier import Densifier
  from autosklearn.pipeline.util import PreprocessingTestCase, _test_preprocessing
label_desc: Use image node_id 2 for calling the DensifierComponentTest obj's underlying member method code with example usage: obj.test_preprocessing_dtype() without return types