class_docstr: Test class for regression tests.
code: def test_ransac_regression(self):
      for base_estimator_name, pearson_value in zip(
          [None, "SGDRegressor", "DecisionTreeRegressor", "SVR"],
          [0.95, 0.95, 0.75, 0.64],
      ):
          yield self.check_ransac_regression, base_estimator_name, pearson_value
  
imports: import math
  import re
  import unittest
  import warnings
  from itertools import chain, product
  import numpy
  from numpy.testing import assert_allclose, assert_array_equal
  from scipy.stats import pearsonr
  from sklearn.exceptions import ConvergenceWarning
  from sklearn.linear_model import LinearRegression, LogisticRegression
  from skll.config import _setup_config_parser
  from skll.data import FeatureSet, NDJReader, NDJWriter
  from skll.experiments import run_configuration
  from skll.learner import Learner
  from skll.learner.utils import rescaled
  from skll.utils.constants import CLASSIFICATION_ONLY_METRICS
  from skll.utils.testing import config_dir, fill_in_config_paths_for_fancy_output, make_regression_data, other_dir, output_dir, test_dir, train_dir, unlink
label_desc: Use image node_id 20 for calling the TestRegression obj's underlying member method code with example usage: obj.test_ransac_regression() without return types