code: def preact_basicblock(l, ch_out, stride, preact):
      l, shortcut = apply_preactivation(l, preact)
      l = Conv2D(
          "conv1", l, ch_out, 3, strides=stride, activation=BNReLU
      )
      l = Conv2D("conv2", l, ch_out, 3)
      return l + resnet_shortcut(shortcut, ch_out, stride)
  
file_path: tensorpack/examples/Saliency/resnet_model.py
imports: import tensorflow
  from tensorpack import tfv1
  from tensorpack.models import BatchNorm, BNReLU, Conv2D, FullyConnected, GlobalAvgPooling, MaxPooling
  from tensorpack.tfutils.argscope import argscope, get_arg_scope
label_desc: Use image node_id 4 for calling a global function with example usage: preact_basicblock(l, ch_out, stride, preact) and returns: unknown