code: def layer_norm(x, w, b, e=1e-5):
      sizes = x.get_output_shape()[1:]
      u = auto.mean(x, len(sizes), True)
      s = auto.mean(auto.square(x - u), len(sizes), True)
      y = (x - u) / auto.sqrt(s + e)
      y = y * w + b
      return y
  
imports: import numpy
  import math
  from bigdl.dllib.nn.layer import Sum
  from bigdl.dllib.nn.layer import Layer
  from bigdl.dllib.utils.file_utils import callZooFunc
  from bigdl.dllib.keras.engine import ZooKerasLayer
  from bigdl.dllib.keras.layers import *
  from bigdl.dllib.keras.models import Sequential
  from bigdl.dllib.keras.models import Model
  import bigdl.dllib.keras.autograd
  from bigdl.dllib.utils.log4Error import *
label_desc: Use image node_id 1 for calling a global function with example usage: layer_norm(x, w, b, e) and returns: y