code: def canon(*rules):
      """Strategy for canonicalization
  
      Apply each branching rule in a top-down fashion through the tree.
      Multiplex through all branching rule traversals
      Keep doing this until there is no change.
      """
      return exhaust(multiplex(*map(top_down, rules)))
  
label_desc: Use image node_id 1 for calling a global function with example usage: canon() and returns: exhaust