code: def load():
      train_x, train_y, val_x, val_y = load_dataset()
      train_x, val_x = normalize(train_x, val_x)
      train_x = train_x.astype(np.float32)
      val_x = val_x.astype(np.float32)
      train_y = train_y.astype(np.int32)
      val_y = val_y.astype(np.int32)
      return train_x, train_y, val_x, val_y
  
file_path: singa/examples/cnn/data/mnist.py
imports: import numpy
  import os
  import sys
  import gzip
  import codecs
label_desc: Use image node_id 7 for calling a global function with example usage: load() and returns: train_x,  train_y,  val_x,  val_y