def main():
root = Node(0)
root.set_right(10)
root.right.set_right(20)
root.right.set_left(5)
root.set_left(-10)
print get_common_ancestor(root.right.right, root.right.left)
def main():
root = Node(0)
root.set_left(-10)
root.set_right(10)
root.left.set_right(-5)
print next_node(root.left, root.left)
root = Node(0)
root.set_left(-10)
root.left.set_right(-5)
root.left.right.set_left(-7)
print next_node(root.left, root.left)
def main():
root = Node(1)
root.set_left(1)
root.left.set_left(2)
root.left.set_right(1)
root.set_right(2)
root.right.set_left(1)
root.right.set_right(1)
root.right.left.set_left(2)
count = [0]
count_all_sums(root, count, 2)
print count
def main():
root = Node(0)
root.set_left(-10)
root.set_right(10)
order = []
pre_order(root, order)
big_root = Node(100)
big_root.set_right(0)
big_root.right.set_left(-10)
big_root.right.set_right(10)
print contains_subtree(big_root, order)