code: def test_simple_multiclass(self):
      self._train_convert_evaluate_assert()
  
imports: import os
  import itertools
  import pandas
  import unittest
  from coremltools._deps import _HAS_SKLEARN
  from coremltools.models.utils import evaluate_classifier, _macos_version, _is_macos
  import pytest
label_desc: Use image node_id 2 for calling the DecisionTreeMultiClassClassificationBostonHousingScikitNumericTest obj's underlying member method code with example usage: obj.test_simple_multiclass() without return types