<doocs>0543.Diameter of Binary Tree_1.py
def dfs(root):
    if root is None:
        return 0
    nonlocal ans
    left, right = dfs(root.left), dfs(root.right)
    ans = max(ans, left + right)
    return 1 + max(left, right)
def sample_funcname ( var_1 ) :
    if var_1 is None :
        return 0
    nonlocal var_4
    left , right = var_0 ( var_1.left ) , var_0 ( var_1.right )
    var_4 = max ( var_4 , left + right )
    return 1 + max ( left , right )
