code: def test_train_process(self):
      self._metric.train()
      result = self._metric.process(self._state)
      self.assertAlmostEqual(2.35, result[0], 3, 0.002)
  
imports: import unittest
  import torch
  from torch.autograd import Variable
  import torchbearer
  from torchbearer.metrics import Loss, Epoch, CategoricalAccuracy, TopKCategoricalAccuracy, BinaryAccuracy, MeanSquaredError
label_desc: Use image node_id 2 for calling the TestLoss obj's underlying member method code with example usage: obj.test_train_process() without return types