如何更改matplotlib工具栏的平移和缩放按钮的模式

import matplotlib.pyplot as plt
from matplotlib.backend_bases import MouseButton

fig, ax = plt.subplots()

# 在这里添加你的绘图代码

toolbar = fig.canvas.toolbar
toolbar.hide()

# 创建平移按钮
pan_button = toolbar._Button('icons/pan.png', 'Pan', 'pan', 'pan', lambda event: toggle_pan(event))
toolbar.pan_button = pan_button

# 创建缩放按钮
zoom_button = toolbar._Button('icons/zoom_to_rect.png', 'Zoom', 'zoom', 'zoom', lambda event: toggle_zoom(event))
toolbar.zoom_button = zoom_button

def toggle_pan(event):
    if event.button == MouseButton.LEFT:
        # 设置平移模式
        ax.set_navigate_mode('pan')

def toggle_zoom(event):
    if event.button == MouseButton.LEFT:
        # 设置缩放模式
        ax.set_navigate_mode('zoom')

plt.show()