Pandas secondary_y:如何在情节之外放置图例？

import pandas as pd
import matplotlib.pyplot as plt

# 创建一个示例数据集
data = {'x': [1, 2, 3, 4, 5],
        'y1': [10, 15, 7, 12, 9],
        'y2': [20, 12, 15, 10, 8]}

df = pd.DataFrame(data)

# 绘制折线图
fig, ax1 = plt.subplots()
ax2 = ax1.twinx()

ax1.plot(df['x'], df['y1'], 'r-', label='y1')
ax2.plot(df['x'], df['y2'], 'b-', label='y2')

# 设置图例
lines, labels = ax1.get_legend_handles_labels()
lines2, labels2 = ax2.get_legend_handles_labels()
ax2.legend(lines + lines2, labels + labels2, loc='upper right')

# 在情节之外放置图例
plt.legend(lines + lines2, labels + labels2, bbox_to_anchor=(1.15, 1), loc='upper right')

plt.show()