SimpleTree.py

#!/usr/bin/env python3

''' Node that carries an integer and a reference to its childs (Nodes)
'''
class Node(object):
    def __init__(self, data):
        self.data = data
        self.children = []

    def append(self, node):
        self.children.append(node)

''' Returns sum of tree, pointed by the root node
'''
def sumTree(node):
    if not node.children:
       return node.data
    sum = node.data
    for child in node.children:
        sum += sumTree(child)
    return sum

node1 = Node(1)
node2 = Node(2)
node3 = Node(3)
node4 = Node(4)
node5 = Node(5)

node1.append(node2)
node1.append(node4)
node2.append(node3)
node3.append(node5)

#                     1
#                     |
#                    /\
#                   2  4
#                   |
#                   3
#                   |
#                   5
print(sumTree(node1))
print(sumTree(node2))
print(sumTree(node3))
print(sumTree(node4))
print(sumTree(node5))