not work

[zhaojiedi1992]

Describe the bug

context
When I do ___.
Uncaught TypeError: Cannot read properties of undefined (reading 'appendChild')
at HTMLDocument.addUtterances (000-开服简介.html:49:17)

expectation
I expected ___ to occur.
Uncaught TypeError: Cannot read properties of undefined (reading 'appendChild')
at HTMLDocument.addUtterances (000-开服简介.html:49:17)

var addUtterances = () => {
var script = document.createElement("script");
script.type = "text/javascript";
script.src = "https://utteranc.es/client.js";
script.async = "async";

script.setAttribute("repo", "zhaojiedi1992/My_Study_MC");
script.setAttribute("issue-term", "pathname");
script.setAttribute("theme", "github-light");
script.setAttribute("label", "💬 comment");
script.setAttribute("crossorigin", "anonymous");

sections = document.querySelectorAll("div.section");
if (sections !== null) {
    section = sections[sections.length-1];   
    section.appendChild(script);   //error here 
}

}

bug
But instead ___ happens
Here's an error message I ran into...

$ jupyter-book build mybook
ERROR ...

problem
This is a problem for people doing ___ because ___.

Reproduce the bug

my conf
comments_config = {
"utterances": {
"repo": "zhaojiedi1992/My_Study_MC",
"issue-term": "pathname",
"theme": "github-light",
"crossorigin": "anonymous" ,
}
}

List your environment

No response

[zhaojiedi1992]

extensions = [
'sphinx_comments',
# ... 其他扩展
]

[zhaojiedi1992]

sphinx-comments
sphinx>=2
sphinx-rtd-theme
sphinx-copybutton