code: def convert_image(image):
      """Convert an image from pixels in {0, ..., 255} to floats in [-1, 1]."""
      image = image * (1.0 / 255) - 0.5
      image *= 2.0
      return image
  
imports: from __future__ import absolute_import
  import numpy
label_desc: Use image node_id 1 for calling a global function with example usage: convert_image(image) and returns: image