如何将标题文本添加到来自figurefactory的两个带注释的热图？

import plotly.figure_factory as ff
import plotly.graph_objects as go

# 创建热图数据
z_data = [[0.8, 0.75, 0.6, 0.5, 0.4],
          [0.6, 0.55, 0.4, 0.3, 0.2],
          [0.4, 0.35, 0.2, 0.1, 0.05],
          [0.2, 0.15, 0.1, 0.05, 0.01]]

# 创建行和列的标签
x_labels = ['A', 'B', 'C', 'D', 'E']
y_labels = ['W', 'X', 'Y', 'Z']

# 创建热图对象
fig = ff.create_annotated_heatmap(z=z_data, x=x_labels, y=y_labels, colorscale='Viridis')

# 设置标题文本
fig.update_layout(title_text='两个带注释的热图')

fig.show()