Root Equals Sum of Children code in python

/**
 * Definition for a binary tree node.
 * struct TreeNode {
 *     int val;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode() : val(0), left(nullptr), right(nullptr) {}
 *     TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
 *     TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {}
 * };
 */
class Solution {
public:
    bool checkTree(TreeNode* root) {
        int sum=0;
        if(root->left!=NULL){
            sum+=root->left->val;
        }
        if(root->right!=NULL){
            sum+=root->right->val;
        }
        if(root->val==sum){
            return true;
        }
        return false;           
        }    
};