code: def _denormalize(self, x):
      if self.affine:
          x = x - self.affine_bias
          x = x / (self.affine_weight + self.eps * self.eps)
      x = x * self.stdev
      if self.subtract_last:
          x = x + self.last
      else:
          x = x + self.mean
      return x
  
imports: import math
  import numpy
  from typing import Optional
  import torch
  import torch.nn
  import torch.nn.functional
  from ..common._base_windows import BaseWindows
  from ..losses.pytorch import MAE
label_desc: Use image node_id 6 for calling the RevIN obj's underlying member method code with example usage: obj._denormalize(x) and returns: x