code: def test_objectmapper(self):
      df = pdml.ModelFrame([])
      self.assertIs(
          df.feature_extraction.DictVectorizer, fe.DictVectorizer
      )
      self.assertIs(
          df.feature_extraction.FeatureHasher, fe.FeatureHasher
      )
  
      self.assertIs(
          df.feature_extraction.image.img_to_graph,
          fe.image.img_to_graph,
      )
      self.assertIs(
          df.feature_extraction.image.grid_to_graph,
          fe.image.grid_to_graph,
      )
      self.assertIs(
          df.feature_extraction.image.extract_patches_2d,
          fe.image.extract_patches_2d,
      )
      self.assertIs(
          df.feature_extraction.image.reconstruct_from_patches_2d,
          fe.image.reconstruct_from_patches_2d,
      )
      self.assertIs(
          df.feature_extraction.image.PatchExtractor,
          fe.image.PatchExtractor,
      )
  
      self.assertIs(
          df.feature_extraction.text.CountVectorizer,
          fe.text.CountVectorizer,
      )
      self.assertIs(
          df.feature_extraction.text.HashingVectorizer,
          fe.text.HashingVectorizer,
      )
      self.assertIs(
          df.feature_extraction.text.TfidfTransformer,
          fe.text.TfidfTransformer,
      )
      self.assertIs(
          df.feature_extraction.text.TfidfVectorizer,
          fe.text.TfidfVectorizer,
      )
  
imports: import sklearn.feature_extraction
  import pandas_ml
  import pandas_ml.util.testing
label_desc: Use image node_id 1 for calling the TestFeatureExtraction obj's underlying member method code with example usage: obj.test_objectmapper() without return types