code: def test_timer(self, mock_perf_counter: mock.MagicMock):
      def test_func(a, b=2):
          return a + b
  
      start_time = 10
      end_time = 12
      mock_perf_counter.side_effect = [start_time, end_time]
  
      with Timer() as timer:
          test_func(1, b=3)
      self.assertAlmostEqual(timer.elapsed_time, end_time - start_time)
  
imports: import copy
  import shutil
  import tempfile
  import unittest
  import unittest.mock
  from pathlib import Path
  import classy_vision.generic.util
  import torch
  import torch.nn
  from classy_vision.generic.util import CHECKPOINT_FILE, get_torch_version, load_checkpoint, save_checkpoint, split_batchnorm_params, Timer, update_classy_model, update_classy_state
  from classy_vision.models import build_model
  from classy_vision.tasks import build_task
  from classy_vision.trainer import LocalTrainer
  from test.generic.config_utils import get_fast_test_task_config, get_test_model_configs
  from test.generic.utils import compare_model_state, compare_states
label_desc: Use image node_id 10 for calling the TestUtilMethods obj's underlying member method code with example usage: obj.test_timer(mock_perf_counter) and returns: unknown