code: def test_train(self):
      self.setUp()
      self._std.train()
      for i in range(5):
          self._std.process(self._metric.process())
      result = self._std.process_final({})
      self.assertAlmostEqual(self._target, result, places=5)
  
imports: import unittest
  from mock import Mock, call
  from torchbearer.metrics import RunningMean, Metric, RunningMetric, Mean, Std, Var
  import torch
label_desc: Use image node_id 2 for calling the TestStd obj's underlying member method code with example usage: obj.test_train() without return types