Hi @JonB,
OK I stumbled upon that post with the script also. On my second and third read and tests in the lastest Pythonista Beta (iPadOS13 and Python 3.6) I did not get it to run.

Update:
Now it worked with the updated version of the post and my x-callback-url inside the script ...

pythonista3://_gears/xcallbackurl/show?action=run&x-things-id=9BD5B336-6AB0-49D9-B3F2-546B52D73375

From there it should be solved easily

THX Felix