如何在heatmap( )中更改图例的标题？

import matplotlib.pyplot as plt
import seaborn as sns

# 创建热力图
data = [[1, 2, 3], [4, 5, 6], [7, 8, 9]]
ax = sns.heatmap(data)

# 获取colorbar对象
for _, spine in ax.spines.items():
    spine.set_visible(False)
for cax in ax.figure.axes:
    cax.yaxis.set_ticks_position('left')
    cax.yaxis.set_label_position('left')
    cax.spines['left'].set_visible(True)
    cax.spines['left'].set_linewidth(1)
    cax.spines['left'].set_color('black')
    cax.spines['left'].set_alpha(0.2)
    cax.set_ylabel('')

# 设置colorbar的标题
for collection in ax.collections:
    if isinstance(collection, plt.cm.ScalarMappable):
        cbar = ax.figure.colorbar(collection)
        cbar.set_label('新的图例标题')

plt.show()