code: def prewhiten(x):
      mean = x.mean()
      std = x.std()
      std_adj = std.clamp(min=1.0 / (float(x.numel()) ** 0.5))
      y = (x - mean) / std_adj
      return y
  
imports: import torch
  from torch import nn
  import numpy
  import os
  from .utils.detect_face import detect_face, extract_face
label_desc: Use image node_id 2 for calling a global function with example usage: prewhiten(x) and returns: y