Inverting Binary Tree in Python

invertingBinaryTreeInPython.py

#!/usr/bin/env python3

class Node():
    """
    Node class used to build a binary tree
    """
    def __init__(self, val):
        self.val = val
        self.left = None
        self.right = None

def printTree(node):
    """
    printTree takes a binary tree (of class Node) and prints it recursively
    """
    print(node.val)
    if node.left != None:
        printTree(node.left)
    if node.right != None:
        printTree(node.right)

def invertBinaryTree(node):
    """
    invertBinaryTree takes a binary tree (of class Node) and inverts it, returning a new inverted binary tree
    """
    if node == None:
        return None

    node.left, node.right = node.right, node.left
    invertBinaryTree(node.left)
    invertBinaryTree(node.right)

    return node

# Initialize tree
tree = Node(1)
tree.left = Node(2)
tree.right = Node(3)
tree.left.left = Node(4)
tree.left.right = Node(5)
tree.right.left = Node(6)
tree.right.right = Node(7)

print("Original tree:\n")
printTree(tree)

invTree = invertBinaryTree(tree)

print("\nInverted tree:\n")
printTree(invTree)