Python Tkinter 如何在下拉菜单中 Select 选项后更新文本

我正试着用Tkinder创建一个菜单.此菜单由多个子菜单组成.
我用for循环构建了一个 struct 来形成这些菜单.
但是，我无法使菜单按钮根据 Select 进行更新

示例代码:

import tkinter as tk
from tkinter import ttk

class Window:
    def __init__(self, master):
        self.categories = {
            "A": {
                "B": {
                    "C": {},
                    "D": {},
                },
                "E": {
                    "F": {}
                }
            },
            "G": {}
        }

        self.menu_button = ttk.Menubutton(master, text = "Select")
        self.top_menu = tk.Menu(self.menu_button, tearoff = False)
        self.menu_button.configure(menu = self.top_menu)
        self.create_category_menu(self.categories, self.top_menu)

        self.menu_button.pack()

    # I created a recursive function, constantly checking subcategories
    def create_category_menu(self, categories, top_menu):
        for category in categories:
            if (len(categories[category]) == 0):
                # if the category has no subcategories, just add the name
                top_menu.add_cascade(label = category)
            else:
                # If there are subcategories, create a separate menu for subcategories
                # and insert it into the top menu
                menu = tk.Menu(top_menu)
                top_menu.add_cascade(label = category, menu = menu)
                self.create_category_menu(categories[category], menu)

root = tk.Tk()
window = Window(root)
root.mainloop()

代码按我想要的方式创建菜单，但我无法将所选选项写入按钮

top_menu.add_cascade(label = category, command = self.func(category))

top_menu.add_cascade(label = category, menu = menu, command = self.func(category))

我像这样更改了这两行，还在代码中创建了以下函数；

def func(self, category):
        self.menu_button["text"] = category

这一次，它将类别词典的底值("G")写入按钮.

共有97个嵌套类别.上面的代码是我为这个问题准备的示例