code: def l2_dist(x, y, pw=False):
      if pw is False:
          x = x.expand_dims(axis=1)
          y = y.expand_dims(axis=0)
  
      return -nd.norm(x - y, ord=2, axis=-1)
  
imports: import os
  import numpy
  import mxnet
  from mxnet import gluon
  from mxnet import ndarray
  from .score_fun import *
  from ..None import *
label_desc: Use image node_id 4 for calling a global function with example usage: l2_dist(x, y, pw) and returns: unknown