code: def test_num_classes_wrong_input():
      with pytest.raises(
          ValueError, match="Argument num_classes needs to be > 1"
      ):
          ConfusionMatrix(num_classes=1)
  
imports: import os
  import numpy
  import pytest
  import torch
  from sklearn.metrics import accuracy_score, confusion_matrix, precision_score, recall_score
  import ignite.distributed
  from ignite.exceptions import NotComputableError
  from ignite.metrics import ConfusionMatrix, IoU, JaccardIndex, mIoU
  from ignite.metrics.confusion_matrix import cmAccuracy, cmPrecision, cmRecall, DiceCoefficient
label_desc: Use image node_id 2 for calling a global function with example usage: test_num_classes_wrong_input() without return types