如何在matplotlib中修改数字堆叠在一起的x轴

import matplotlib.pyplot as plt

x = [1, 2, 3, 4]
y1 = [1, 2, 3, 4]
y2 = [2, 3, 4, 5]
y3 = [3, 4, 5, 6]

plt.bar(x, y1, label='y1')
plt.bar(x, y2, bottom=y1, label='y2')
plt.bar(x, y3, bottom=[i+j for i,j in zip(y1, y2)], label='y3')

plt.xticks(x, ['A', 'B', 'C', 'D'])

plt.legend()
plt.show()

import matplotlib.pyplot as plt

x = [1, 2, 3, 4]
y1 = [1, 2, 3, 4]
y2 = [2, 3, 4, 5]
y3 = [3, 4, 5, 6]

plt.bar(x, y1, label='y1')
plt.bar(x, y2, bottom=y1, label='y2')
plt.bar(x, y3, bottom=[i+j for i,j in zip(y1, y2)], label='y3')

plt.xticks(x, ['A', 'B', 'C', 'D'])

plt.legend()
plt.show()