Sum of all right leaf nodes of binary tree in python

Python program for Sum of all right leaf nodes of binary tree. Here mentioned other language solution.

#    Python 3 program for
#    Sum of all right leaves nodes in a binary tree
#    Using recursion

#  Binary Tree node
class TreeNode :
    def __init__(self, data) :
        #  Set node value
        self.data = data
        self.left = None
        self.right = None
class BinaryTree :
    def __init__(self) :
        #  Set initial tree root
        self.root = None
    #  Display pre order elements
    def preorder(self, node) :
        if (node != None) :
            #  Print node value
            print("",node.data, end =" ")
            self.preorder(node.left)
            self.preorder(node.right)
    #  Returns the Sum of all the right leaves in binary tree
    def  rightLeavesSum(self, node) :
        sum = 0
        if (node != None) :
            if (node.right != None and 
                node.right.left == None and 
                node.right.right == None) :
                #  When get right leaf node
                sum = node.right.data
            #  Recursively visit left and right subtree.
            #  And find sum of right leaf nodes
            sum = sum + self.rightLeavesSum(node.left) + \
            self.rightLeavesSum(node.right)
        return  sum
def main() :
    #  New binary tree
    tree = BinaryTree()
    #    Constructor binary tree
    #    -----------------------
    #          6
    #         / \ 
    #        /   \                             
    #       /     \    
    #      2       3     
    #     / \       \               
    #    8   10      1
    #       /  \    / \
    #      6   -2  4   5
    #  Add tree node
    tree.root = TreeNode(6)
    tree.root.left = TreeNode(2)
    tree.root.left.left = TreeNode(8)
    tree.root.left.right = TreeNode(10)
    tree.root.left.right.right = TreeNode(-2)
    tree.root.left.right.left = TreeNode(6)
    tree.root.right = TreeNode(3)
    tree.root.right.right = TreeNode(1)
    tree.root.right.right.left = TreeNode(4)
    tree.root.right.right.right = TreeNode(5)
    print("\n Tree Nodes : ", end ="")
    tree.preorder(tree.root)
    #  Find right leaf sum
    sum = tree.rightLeavesSum(tree.root)
    #  Display result
    print("\n Right leaves nodes sum :",sum)


if __name__=="__main__":
    main()

Output

 Tree Nodes :  6  2  8  10  6  -2  3  1  4  5
 Right leaves nodes sum : 3