code: def test_empty_methods(self):
      metric = Metric(name="test")
      self.assertTrue(metric.process() is None)
      self.assertTrue(metric.process_final() is None)
  
imports: import unittest
  from mock import Mock, MagicMock, create_autospec, patch
  import torch
  import torchbearer
  from torchbearer.bases import Metric, Callback, base_closure
  from torchbearer.metrics.primitives import CategoricalAccuracy
label_desc: Use image node_id 3 for calling the TestMetric obj's underlying member method code with example usage: obj.test_empty_methods() without return types