code: def test_pos_label_not_in_data(self):
      expected_msg = "Must have pos_label in y values"
      with pytest.raises(ValueError) as e0:
          _get_labels_for_confusion_matrix([0, 1], -1)
      assert str(e0.value) == expected_msg
      with pytest.raises(ValueError) as e1:
          _get_labels_for_confusion_matrix([4, 2], 3)
      assert str(e1.value) == expected_msg
  
imports: import numpy
  import pytest
  import sklearn.metrics
  import fairlearn.metrics
  from fairlearn.metrics._base_metrics import _get_labels_for_confusion_matrix
label_desc: Use image node_id 9 for calling the TestGetLabelsForConfusionMatrix obj's underlying member method code with example usage: obj.test_pos_label_not_in_data() without return types