code: def DownsampleFactory(data, ch_3x3, name, attr):
      # conv 3x3
      conv = ConvFactory(
          data=data,
          name=name + "_conv",
          kernel=(3, 3),
          stride=(2, 2),
          num_filter=ch_3x3,
          pad=(1, 1),
          attr=attr,
      )
      # pool
      pool = mx.symbol.Pooling(
          data=data,
          name=name + "_pool",
          kernel=(3, 3),
          stride=(2, 2),
          pad=(1, 1),
          pool_type="max",
          attr=attr,
      )
      # concat
      concat = mx.symbol.Concat(*[conv, pool], name=name + "_ch_concat")
      return concat
  
imports: import mxnet
label_desc: Use image node_id 4 for calling a global function with example usage: DownsampleFactory(data, ch_3x3, name, attr) and returns: concat