如何在Tkinter中对Treeview的值求和

import tkinter as tk
from tkinter import ttk

root = tk.Tk()

tree = ttk.Treeview(root, columns=("Name", "Value"))
tree.pack()

tree.insert("", "0", text="Item 1", values=("Item 1", 10))
tree.insert("", "1", text="Item 2", values=("Item 2", 20))
tree.insert("", "end", text="Item 3", values=("Item 3", 30))

def calculate_sum():
    total = 0
    for item in tree.get_children():
        value = int(tree.item(item, "values")[1])
        total += value
    print("Sum:", total)

button = tk.Button(root, text="Calculate Sum", command=calculate_sum)
button.pack()

root.mainloop()