code: def shortcut(self, input, ch_out, stride, is_first, name):
      ch_in = input.shape[1]
      if ch_in != ch_out or stride != 1 or is_first == True:
          return self.conv_bn_layer(input, ch_out, 1, stride, name=name)
      else:
          return input
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  from builtins import chr
  from builtins import str
  from builtins import range
  from builtins import object
  import math
  import paddle
  import paddle.fluid
  from paddle.fluid.param_attr import ParamAttr
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, is_first, name) and returns: self, input