code: def normalize(image, label):
      """Standardization of MNIST images."""
      x = tf.cast(image, tf.float32) / 255.0
      image = (x - 0.1307) / 0.3081  # image = (x - mean) / std
      return image, label
  
file_path: tf-encrypted/tf_encrypted/keras/datasets/convert.py
imports: import tensorflow
label_desc: Use image node_id 7 for calling a global function with example usage: normalize(image, label) and returns: image,  label