code: def print_tree(lb):
      """
      Print the tree of layoutboxes
      """
  
      if lb.parent is None:
          print("LayoutBox Tree\n")
          print("==============\n")
          print_children(lb)
          print("\n")
      else:
          print_tree(lb.parent)
  
imports: from __future__ import absolute_import, division, print_function, unicode_literals
  import itertools
  import kiwisolver
  import logging
  import numpy
  import warnings
  import matplotlib
label_desc: Use image node_id 22 for calling a global function with example usage: print_tree(lb) without return types