Customdata in texttemplate could not be found in heatmap

For a heatmap chart I want to create a hyperlink, which is provided in the customdata. For some reason it looks like the customdata fields is not accessible from the texttemplate field. Executing the sample code below with browser debug mode shows that customdata is not found:

import plotly.graph_objects as go
labels = ["a", "b", "c"]
z = [[1, 2, 3], [4, 5, 6], [7, 8, 9]]
customdata = [["http://google.com", "http://google.com", "http://google.com"], ["http://google.com", "http://google.com", "http://google.com"], ["http://google.com", "http://google.com", "http://google.com"]]
fig = go.Figure(data=go.Heatmap(x=labels, y=labels,
                                z=z,
                                customdata=customdata,
                                texttemplate="""<a href="%{customdata}">%{z}</a>""",
                                hovertemplate='%{customdata}<extra></extra>',
                                textfont={"size": 20}))
fig.show()

从提供的 Python heatmap 示例开始，跟踪 Heatmap customdata 如何传递给 texttemplate，并将其与正常工作的 hovertemplate 行为进行比较。通过使用 customdata URL 渲染超链接，并检查现有的 hover 文本是否仍能正确显示，确认 fix。