code: def mse_loss(input, target):
      e = ((input - target) ** 2).mean(axis=0, exclude=True)
      return e
  
imports: import argparse
  import random
  from mxnet import gluon, image, autograd
  from mxnet.gluon.data.vision import transforms
  from mxnet.gluon.data import DataLoader
  from mxnet.gluon import nn
  import mxnet.ndarray
  import mxnet
  from mxboard import SummaryWriter
  import os
  from mxnet.gluon.model_zoo import vision
label_desc: Use image node_id 4 for calling a global function with example usage: mse_loss(input, target) and returns: e