Count Good Nodes in Binary Tree

# Definition for a binary tree node.
# class TreeNode:
#     def __init__(self, val=0, left=None, right=None):
#         self.val = val
#         self.left = left
#         self.right = right

class Solution:
    def goodNodes(self, root: TreeNode) -> int:

      def checkNode(node,val):
        if(node == None):
            return 0

        op = 0
        if(node.val >= val):
            op = 1

        val = max(val,node.val)
        return op + checkNode(node.left,val) + checkNode(node.right,val)

      return checkNode(root,root.val)