如何在tkinter画布上更新matplotlib子图？

import tkinter as tk
from matplotlib.backends.backend_tkagg import FigureCanvasTkAgg
from matplotlib.figure import Figure

root = tk.Tk()
canvas = tk.Canvas(root, width=500, height=500)
canvas.pack()

fig = Figure(figsize=(5, 5), dpi=100)
subplot = fig.add_subplot(111)

def update_plot():
    # 在这里更新子图的内容
    subplot.plot([1, 2, 3, 4], [1, 4, 9, 16])
    canvas.draw()

button = tk.Button(root, text="更新子图", command=update_plot)
button.pack()

canvas = FigureCanvasTkAgg(fig, master=canvas)
canvas.draw()
canvas.get_tk_widget().pack()

tk.mainloop()