I tried to follow the instructions exactly, but it was terrible. First, the page is blank, and devtool displays:

Uncaught SyntaxError: Invalid or unexpected token (at parentPortal:6:37)

contentScript.js:5

Uncaught ReferenceError: browser is not defined

    at contentScript.js:5:5

Then I added website=True (thanks to GPT) to  @route("/tutoringCentre/parentPortal", auth="public", csrf=True), finally there is a view on the browser, but the previous two errors still exist!! I have checked my code countless times, and I still don’t know why...