code: def get_data():
      train = BatchData(dataset.Mnist("train"), 128)
      test = BatchData(dataset.Mnist("test"), 256, remainder=True)
      return train, test
  
file_path: tensorpack/examples/basics/mnist-visualizations.py
imports: from tensorpack import tfv1
  from tensorpack import *
  from tensorpack.dataflow import dataset
label_desc: Use image node_id 3 for calling a global function with example usage: get_data() and returns: train,  test