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(TypeError):
          model = NuSVR()
          spec = scikit_converter.convert(model, "data", "out")
  
      # Check the expected class during conversion.
      with self.assertRaises(TypeError):
          model = OneHotEncoder()
          spec = scikit_converter.convert(model, "data", "out")
  
imports: import random
  import tempfile
  import unittest
  import pandas
  import pytest
  from coremltools._deps import _HAS_LIBSVM, _HAS_SKLEARN, MSG_LIBSVM_NOT_FOUND, MSG_SKLEARN_NOT_FOUND
  from coremltools.models.utils import _is_macos, _macos_version, evaluate_regressor
label_desc: Use image node_id 2 for calling the NuSVRScikitTest obj's underlying member method code with example usage: obj.test_conversion_bad_inputs() without return types