a generic tree in python

category_tree.py

# generic tree in python
# to demostrate a category tree

class Tree:
    def __init__(self):
        self.roots = []

    def add_root(self, val):
        node = Node(val)
        self.roots.append(node)
        return node

    def add_child(self, parent, val):
        return parent.add_child(val)

    def get_children(self, parent):
        # get all the children in a parent
        for child in parent.children:
            print("child:", child.value)

class Node:
    def __init__(self, val):
        self.children = []
        self.value = val

    def add_child(self, val):
        n = Node(val)
        self.children.append(n)
        return n


t = Tree()
n1 = t.add_root(1)
n2 = t.add_root(2)
n11 = n1.add_child(11)
n12 = n1.add_child(12)
n13 = t.add_child(n1, 13)

n2.add_child(21)

print("children of node:1")
t.get_children(n1)

print("children of node:2")
t.get_children(n2)