code: def test_classifier_score_with_None(y, y_test):
      clf = DummyClassifier(strategy="most_frequent")
      clf.fit(None, y)
      assert clf.score(None, y_test) == 0.5
  
imports: import numpy
  import pytest
  import scipy.sparse
  from sklearn.base import clone
  from sklearn.dummy import DummyClassifier, DummyRegressor
  from sklearn.exceptions import NotFittedError
  from sklearn.utils._testing import assert_almost_equal, assert_array_almost_equal, assert_array_equal, ignore_warnings
  from sklearn.utils.fixes import CSC_CONTAINERS
  from sklearn.utils.stats import _weighted_percentile
label_desc: Use image node_id 13 for calling a global function with example usage: test_classifier_score_with_None(y, y_test) without return types