如何使用python matplotlib的艺术家图层在条形图上显示百分比值

import matplotlib.pyplot as plt
import numpy as np

categories = ['A', 'B', 'C', 'D']
values = [20, 35, 40, 15]

fig, ax = plt.subplots()
bars = ax.bar(categories, values)

total = sum(values)
percentages = [f'{(v/total)*100:.2f}%' for v in values]

for bar, percentage in zip(bars, percentages):
    height = bar.get_height()
    ax.text(bar.get_x() + bar.get_width() / 2, height, percentage,
            ha='center', va='bottom')

ax.set_title('Bar Chart with Percentages')
ax.set_xlabel('Categories')
ax.set_ylabel('Values')

plt.show()