如何在Python绘图堆叠条形图中显示多个文本和文本位置

import matplotlib.pyplot as plt
import numpy as np

categories = ['Category A', 'Category B', 'Category C']
values1 = [10, 15, 12]
values2 = [8, 10, 14]
values3 = [12, 9, 11]

fig, ax = plt.subplots()

bar1 = ax.bar(categories, values1)
bar2 = ax.bar(categories, values2, bottom=values1)
bar3 = ax.bar(categories, values3, bottom=np.add(values1, values2))

for i, (bar, val1, val2, val3) in enumerate(zip(bar1, values1, values2, values3)):
    height = bar.get_height()
    ax.text(bar.get_x() + bar.get_width() / 2, height, f'{val1}', ha='center', va='bottom')
    ax.text(bar.get_x() + bar.get_width() / 2, height + val2 / 2, f'{val2}', ha='center', va='center')
    ax.text(bar.get_x() + bar.get_width() / 2, height + val2 + val3 / 2, f'{val3}', ha='center', va='center')

ax.legend(['Value 1', 'Value 2', 'Value 3'])
ax.set_xlabel('Categories')
ax.set_ylabel('Values')

plt.show()