class_docstr: Unit test class for testing scikit-learn converter.
code: def test_conversion_bad_inputs(self):
      # Error on converting an untrained model
      with self.assertRaises(Exception):
          model = DecisionTreeClassifier()
          spec = skl_converter(model, "data", "out")
  
      # Check the expected class during conversion.
      from sklearn.preprocessing import OneHotEncoder
  
      with self.assertRaises(Exception):
          model = OneHotEncoder()
          spec = skl_converter(model, "data", "out")
  
file_path: coremltools/coremltools/test/xgboost_tests/test_decision_tree_classifier.py
imports: import unittest
  from coremltools._deps import _HAS_SKLEARN, _HAS_XGBOOST
label_desc: Use image node_id 3 for calling the DecisionTreeBinaryClassifierScikitTest obj's underlying member method code with example usage: obj.test_conversion_bad_inputs() without return types