code: def test_std_dim(self):
      std = Std("test", dim=0)
      std.process(torch.Tensor([[1.0, 2.0], [3.0, 4.0]]))
      std.process(torch.Tensor([[4.0, 3.0], [2.0, 1.0]]))
      std.process(torch.Tensor([[1.0, 1.0], [1.0, 1.0]]))
  
      res = std.process_final()
      self.assertTrue(len(res) == 2)
      for m in res:
          self.assertTrue(abs(m - 1.2649) < 0.0001)
  
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 7 for calling the TestStd obj's underlying member method code with example usage: obj.test_std_dim() without return types