如何在tkinter python中的两个函数之间传递变量？

import tkinter as tk

def function1():
    global my_variable
    my_variable = "Hello"

def function2():
    print(my_variable)

root = tk.Tk()
button1 = tk.Button(root, text="Function 1", command=function1)
button1.pack()
button2 = tk.Button(root, text="Function 2", command=function2)
button2.pack()
root.mainloop()

import tkinter as tk

class MyApplication:
    def __init__(self):
        self.my_variable = ""

    def function1(self):
        self.my_variable = "Hello"

    def function2(self):
        print(self.my_variable)

app = MyApplication()
root = tk.Tk()
button1 = tk.Button(root, text="Function 1", command=app.function1)
button1.pack()
button2 = tk.Button(root, text="Function 2", command=app.function2)
button2.pack()
root.mainloop()

import tkinter as tk

def function1(variable):
    variable.set("Hello")

def function2(variable):
    print(variable.get())

root = tk.Tk()
my_variable = tk.StringVar()
button1 = tk.Button(root, text="Function 1", command=lambda: function1(my_variable))
button1.pack()
button2 = tk.Button(root, text="Function 2", command=lambda: function2(my_variable))
button2.pack()
root.mainloop()