class Tree:

# We create the basic structure of the tree. Children nodes can be keep in

# a different data structure, such as: a lists or a dictionary. In this

# example we manage the children nodes in a dictionary.

def __init__(self, node_id, value=None, parent_id=None):

self.node_id = node_id

self.parent_id = parent_id

self.value = value

self.children = {}

def add_node(self, node_id, value=None, parent_id=None):

# Every time that we add a node, we need to verify the parent of the

# new node. If it is not the parent, we search recursively through the

# the tree until we the right parent node.

if self.node_id == parent_id:

# If the node is the parent, we update the dictionary with the

# children.

self.children.update({node_id: Tree(node_id, value, parent_id)})

else:

# If the node is not the parent we search recursively

for child in self.children.values():

child.add_node(node_id, value, parent_id)

def get_node(self, node_id):

# We recursively get the node as long as it exist in the tree

# recursivamente obtenemos el node siempre y cuando exista

# la posicion.

if self.node_id == node_id:

return self

else:

for child in self.children.values():

node = child.get_node(node_id)

if node:

# if exist the node in the tree, returns the node

return node

def __repr__(self):

# We override this method in order to traverse recursively the node in

# the tree.

def traverse_tree(root):

for child in root.children.values():

self.ret += "id-node: {} -> parent_id: {} -> value: {}\n".format(

child.node_id, child.parent_id, child.value)

traverse_tree(child)

return self

self.ret = 'root:\nroot-id: {} -> value: {}\n\nchildren:\n'.format(

self.node_id, self.value)

traverse_tree(self)

return self.ret