code: def _upsample(x):
      return F.unpooling_2d(x, 2, cover_all=False)
  
imports: from __future__ import division
  import itertools
  import numpy
  import chainer
  from chainer.backends import cuda
  import chainer.functions
  from chainer.links import Convolution2D
  from chainercv.links import Conv2DBNActiv
  from chainercv import utils
  from chainercv.links.model.yolo.yolo_base import YOLOBase
label_desc: Use image node_id 2 for calling a global function with example usage: _upsample(x) and returns: F