如何使用matplotlib和gridspec将一个轴与其他轴隔开？

import matplotlib.pyplot as plt
import matplotlib.gridspec as gridspec

fig = plt.figure(figsize=(8, 6))
gs = gridspec.GridSpec(2, 2)

ax1 = fig.add_subplot(gs[0, 0])
ax2 = fig.add_subplot(gs[0, 1])
ax3 = fig.add_subplot(gs[1, :])

ax1.plot([1, 2, 3], [4, 5, 6])
ax1.set_title('Plot 1')

ax2.bar(['A', 'B', 'C'], [7, 8, 9])
ax2.set_title('Plot 2')

ax3.scatter([1, 2, 3], [4, 5, 6])
ax3.set_title('Plot 3')

gs.update(hspace=0.5)
plt.tight_layout()

plt.show()