Render PDF form with contents

What I’m trying to do:
Render pdf form that includes the inputs of the user.
What I’ve tried and what’s not working:
I tried anvil.pdf.render_form(‘Form1’) but the form rendered is empty.
Code Sample:

# this is a formatted code snippet.
# paste your code between ``` 

Clone link:
share a copy of your app

This has been covered in other forum posts, e.g. PDFRendered: Unable to render a form in its most up-to-date state - #4 by jshaffstall