code: def test_confusion_matrix(self):
      with self.assertRaisesRegex(ValueError, "needed to plot"):
          plot.confusion_matrix(None, [1, 0])
  
file_path: sklearn-evaluation/tests/test_plot_input.py
imports: from unittest import TestCase
  from sklearn_evaluation import plot
label_desc: Use image node_id 1 for calling the TestMissingInput obj's underlying member method code with example usage: obj.test_confusion_matrix() without return types