如何配置MatPlotLib工具栏，使工具栏中的按钮为ttk按钮，而不是旧的Tk按钮

import matplotlib.pyplot as plt
from matplotlib.backends.backend_tkagg import NavigationToolbar2Tk
from matplotlib.backends.backend_tkagg import FigureCanvasTkAgg
from tkinter import ttk
import tkinter as tk

root = tk.Tk()
root.title("Matplotlib Toolbar")

fig = plt.figure(figsize=(6, 4), dpi=100)
ax = fig.add_subplot(111)
ax.plot([1, 2, 3, 4, 5], [1, 4, 9, 16, 25])

canvas = FigureCanvasTkAgg(fig, master=root)
canvas.draw()
canvas.get_tk_widget().pack(side=tk.TOP, fill=tk.BOTH, expand=1)

toolbar = NavigationToolbar2Tk(canvas, root)
toolbar.update()
toolbar.pack(side=tk.TOP, fill=tk.BOTH, expand=1)

for child in toolbar.winfo_children():
    if isinstance(child, tk.Button):
        child.pack_forget()
        ttk.Button(toolbar, text=child['text'], command=child['command']).pack(side=tk.LEFT)

tk.mainloop()