code: def shortcut(self, input, ch_out, stride):
      ch_in = input.shape[1]
      if ch_in != ch_out or stride != 1:
          return self.conv_bn_layer(input, ch_out, 1, stride)
      else:
          return input
  
imports: from __future__ import division
  from builtins import range
  from builtins import object
  from past.utils import old_div
  import paddle.fluid
  import math
label_desc: Use image node_id 4 for calling the ResNet obj's underlying member method code with example usage: obj.shortcut(input, ch_out, stride) and returns: self, input