code: def test_fit_linear_multi_l2r(mult_dense_train_data):
      mult_dense, mult_target = mult_dense_train_data
      clf = CDClassifier(C=1.0, random_state=0, penalty="l2")
      clf.fit(mult_dense, mult_target)
      acc = clf.score(mult_dense, mult_target)
      np.testing.assert_almost_equal(acc, 0.8833, 4)
  
imports: import numpy
  import pytest
  from sklearn.datasets import load_digits
  from sklearn.preprocessing import LabelBinarizer
  from lightning.impl.primal_cd import CDClassifier, CDRegressor
  from lightning.impl.tests.utils import check_predict_proba
label_desc: Use image node_id 13 for calling a global function with example usage: test_fit_linear_multi_l2r(mult_dense_train_data) without return types