code: def test_missing_classes():
      labels = [0, 1]  # class 2 is missing
      pred_probs = np.array([[0.8, 0.1, 0.1], [0.4, 0.5, 0.1]])
      assert get_missing_classes(labels, pred_probs=pred_probs) == [2]
  
imports: from cleanlab.internal import util
  import numpy
  import pytest
  from cleanlab.internal.label_quality_utils import get_normalized_entropy
  from cleanlab.internal.multilabel_utils import int2onehot, onehot2int
  from cleanlab.internal.util import num_unique_classes, format_labels, get_missing_classes
  from cleanlab.internal.validation import assert_valid_class_labels
label_desc: Use image node_id 11 for calling a global function with example usage: test_missing_classes() without return types