class_docstr: Test class for first set of voting learner API tests.
code: def test_initialize(self):
      for (
          learner_type,
          voting_type,
          feature_scaling,
          pos_label,
          min_feature_count,
          model_kwargs_list,
          sampler_list,
      ) in product(
          ["classifier", "regressor"],
          [None, "hard", "soft"],
          [None, "none", "both", "with_mean", "with_std"],
          [None, "a"],
          [None, 5],
          [None, True],
          [None, True],
      ):
          yield (
              self.check_initialize,
              learner_type,
              voting_type,
              feature_scaling,
              pos_label,
              min_feature_count,
              model_kwargs_list,
              sampler_list,
          )
  
imports: import unittest
  from itertools import product
  from pathlib import Path
  import numpy
  from numpy.testing import assert_raises_regex
  from sklearn.ensemble import RandomForestRegressor, VotingClassifier, VotingRegressor
  from sklearn.linear_model import LinearRegression, LogisticRegression
  from sklearn.naive_bayes import MultinomialNB
  from sklearn.pipeline import Pipeline
  from sklearn.svm import SVC, SVR
  from skll.learner.voting import VotingLearner
  from skll.utils.testing import make_california_housing_data, make_digits_data, other_dir, output_dir
label_desc: Use image node_id 4 for calling the TestVotingLearnersAPIOne obj's underlying member method code with example usage: obj.test_initialize() without return types