Second largest element in BST in python

Python program for Second largest element in BST. Here mentioned other language solution.

#  Python 3 program for
#  Second largest element in BST
class TreeNode :
	def __init__(self, data) :
		self.data = data
		self.left = None
		self.right = None

class BinarySearchTree :
	def __init__(self) :
		self.root = None
		self.result = None
		self.counter = 0
	
	#  Insert a node element
	def addNode(self, data) :
		#  Create a new node
		node = TreeNode(data)
		if (self.root == None) :
			#  When adds a first node in bst
			self.root = node
		else :
			find = self.root
			#  Add new node to proper position
			while (find != None) :
				if (find.data >= data) :
					if (find.left == None) :
						#  When left child empty
						#  So add new node here
						find.left = node
						return
					else :
						#  Otherwise
						#  Visit left sub-tree
						find = find.left
					
				else :
					if (find.right == None) :
						#  When right child empty
						#  So add new node here
						find.right = node
						return
					else :
						#  Visit right sub-tree
						find = find.right

	#  Find second largest element in a binary search tree
	def findSecondBig(self, node) :
		if (node != None) :
			#  Visit to right subtree
			self.findSecondBig(node.right)
			if (self.counter == 2) :
				return
			
			if (self.result == None or 
                self.result.data > node.data) :
				#  Modified counter variable by one
				self.counter += 1
				self.result = node
			
			#  Visit to left subtree
			self.findSecondBig(node.left)
		
	
	def secondLargest(self) :
		if (self.root == None) :
			#  When BST are empty
			print("Empty Binary Search Tree")
		else :
			#  Reset value
			self.counter = 0
			self.result = None
			#  Find second largest
			self.findSecondBig(self.root)
			if (self.result == None or self.counter < 2) :
				#  If In case 2nd Largest node are
				#  Not exist in binary search tree
				print("Second Largest node are not exist")
			else :
				print("Second largest node : ", self.result.data)

def main() :
	tree = BinarySearchTree()
	#  Binary Search Tree
	#  -------------------
	#        7
	#       / \
	#      /   \
	#     4     10
	#    / \   / \
	#   3   5 8   10
	#          \    \
	#           9   10
	#  Add node
	tree.addNode(7)
	tree.addNode(4)
	tree.addNode(3)
	tree.addNode(5)
	tree.addNode(10)
	tree.addNode(8)
	tree.addNode(10)
	tree.addNode(9)
	tree.addNode(10)
	tree.secondLargest()

if __name__ == "__main__": main()

Output

Second largest node :  9