code: def _upsample(x, stride=2):
      """Simple upsampling layer by stack pixel alongside horizontal and vertical directions.
      Parameters
      ----------
      x : mxnet.nd.NDArray or mxnet.symbol.Symbol
          The input array.
      stride : int, default is 2
          Upsampling stride
      """
      return x.repeat(axis=-1, repeats=stride).repeat(
          axis=-2, repeats=stride
      )
  
imports: from __future__ import absolute_import
  from __future__ import division
  import os
  import warnings
  import numpy
  import mxnet
  from mxnet import gluon
  from mxnet import autograd
  from mxnet.gluon import nn
  from mxnet.gluon.nn import BatchNorm
  from .darknet import _conv2d, darknet53
  from ..mobilenet import get_mobilenet
  from .yolo_target import YOLOV3TargetMerger
  from ...loss import YOLOV3Loss
label_desc: Use image node_id 1 for calling a global function with example usage: _upsample(x, stride) and returns: x