code: def test_num_classes_wrong_input():
      with pytest.raises(
          ValueError, match="Argument num_classes needs to be > 1"
      ):
          MultiLabelConfusionMatrix(num_classes=1)
  
file_path: ignite/tests/ignite/metrics/test_multilabel_confusion_matrix.py
imports: import numpy
  import pytest
  import torch
  from sklearn.metrics import multilabel_confusion_matrix
  import ignite.distributed
  from ignite.exceptions import NotComputableError
  from ignite.metrics.multilabel_confusion_matrix import MultiLabelConfusionMatrix
label_desc: Use image node_id 2 for calling a global function with example usage: test_num_classes_wrong_input() without return types