code: def forward(self, x):
      vars = torch.var(x, dim=(2, 3), keepdim=True)
      h = x / torch.sqrt(vars + 1e-5)
  
      out = self.alpha.view(-1, self.num_features, 1, 1) * h
      return out
  
imports: import functools
  import torch
  import torch.nn
label_desc: Use image node_id 2 for calling the VarianceNorm2d obj's underlying member method code with example usage: obj.forward(x) and returns: out