code: def build_preprocess_fn(cls, args, train):
      return None
  
imports: import configargparse
  import pytest
  import torch
  from espnet2.tasks.abs_task import AbsTask
  from espnet2.torch_utils.device_funcs import force_gatherable
  from espnet2.train.abs_espnet_model import AbsESPnetModel
  from espnet2.train.collate_fn import CommonCollateFn
label_desc: Use image node_id 3 for calling the TestTask obj's underlying member method code with example usage: obj.build_preprocess_fn(cls, args, train) and returns: None