iterate_tree.py

class Node:
  def __init__(self, name, children):
    self.name = name
    self.children = children

tree = Node(1, [
  Node(2, [
    Node(3, [
      Node(4, []),
      Node(5, [
        Node(6,[])
      ]),
    ]),
    Node(7, [
      Node(8, []),
      Node(9, []),
    ]),
  ]),
  Node(10, [
    Node(11, []),
    Node(12, [
      Node(13, []),
      Node(14, [
        Node(15, []),
      ]),
    ])
  ]),
  Node(16, []),
])

def iterate(tree):
  stack = []
  stack.append(iter([tree]))
  while stack:
    iterator = stack[-1]
    try:
      node = iterator.next()
      yield node
      stack.append(iter(node.children))
    except:
      stack.pop()

for node in iterate(tree):
  print node.name