Setting notes of Keynote slide to an empty string --- not working

Hi all. I’m fairly new, so may be missing something obvious. I wish to remove the presenter notes in a Keynote presentation entirely. I’ve written the following:

display alert “This dialog will remove the notes in your presentation. Proceed anyway?” buttons {“Cancel”, “Proceed”} default button “Cancel”
if button returned of result is “Cancel” then tell me to quit

set nothing to ""

tell application "Keynote"
	tell slideshow 1
		repeat with x in every slide
			tell x
				set notes to nothing as string
			end tell
		end repeat
	end tell
end tell

Unfortunately, nothing changes in the presentation when I run this. If I change

  set nothing to ""


  set nothing to "Monty Python", or more usefully,
  set nothing to " "

the notes are all replaced with Monty Python or a single space, respectively. So, the replacing bit is working, it is the interpretation of


that I’m not getting. Can anyone help?



same behavior here. I regards this as a bug