code: def setUpClass(self):
      # Load data and train model
      scikit_data = load_boston()
      self.scikit_data = scikit_data
      self.X = scikit_data["data"]
      self.target = scikit_data["target"]
      self.feature_names = scikit_data.feature_names
      self.output_name = "target"
  
imports: import unittest
  import pandas
  import itertools
  import pytest
  from coremltools._deps import _HAS_SKLEARN, _HAS_XGBOOST
  from coremltools.models.utils import evaluate_regressor, _macos_version, _is_macos
label_desc: Use image node_id 1 for calling the GradientBoostingRegressorBostonHousingScikitNumericTest obj's underlying member method code with example usage: obj.setUpClass() without return types