code: def update(self, preds: torch.Tensor, target: torch.Tensor):
      pass
  
imports: import os
  import unittest
  from unittest import skipIf
  from unittest.mock import ANY
  import numpy
  import torch
  import torch.nn
  import torchmetrics
  from poutyne import Metric, Model, do_register_metric_class, rename_doubles, unregister_metric_class
label_desc: Use image node_id 2 for calling the MyConstTorchMetric obj's underlying member method code with example usage: obj.update(preds, target) without return types