code: def test_compositional_metrics_update():
      """Test update method for compositional metrics."""
      compos = DummyMetric(5) + DummyMetric(4)
  
      assert isinstance(compos, CompositionalMetric)
      compos.update()
      compos.update()
      compos.update()
  
      assert isinstance(compos.metric_a, DummyMetric)
      assert isinstance(compos.metric_b, DummyMetric)
  
      assert compos.metric_a._num_updates == 3
      assert compos.metric_b._num_updates == 3
  
imports: from operator import neg, pos
  from typing import Any
  import pytest
  import torch
  from torch import tensor
  from torchmetrics.metric import CompositionalMetric, Metric
label_desc: Use image node_id 29 for calling a global function with example usage: test_compositional_metrics_update() without return types