python:如何添加第三个或更多x轴？

import matplotlib.pyplot as plt
import numpy as np

fig, ax1 = plt.subplots()

x1 = np.array([1, 2, 3, 4, 5])
y1 = np.array([2, 4, 6, 8, 10])
ax1.plot(x1, y1, 'r-', label='First X-axis')

ax2 = ax1.twiny()

x2 = np.array([10, 20, 30, 40, 50])
y2 = np.array([1, 3, 5, 7, 9])
ax2.plot(x2, y2, 'g-', label='Second X-axis')

ax3 = ax1.twiny()

ax3.spines['top'].set_position(('outward', 60))
ax3.set_xlabel('Third X-axis')

fig.legend(loc='upper right')
plt.show()