"Simple Calendar Code" doesn't work in Renpy 7

[MadeVeryMerry]

Hi! Sorry if this is going to be a silly question. Due to time restraints, my Ren'Py project development lapsed for a year, and so I'm working a little bit out of date.

So when I was previously working on the project (last November) I set up my in-game calendar exactly how I want it using this code, in Ren'Py 6.99.12.4. It works fine in that version, but since a new version was just released, I wanted to port my files over to the new version and work with that. Unfortunately, when I try to launch the same project from Ren'Py 7.1.3, I get this error code:

Code: Select all

I'm sorry, but an uncaught exception occurred.

While running game code:
  File "renpy/common/00start.rpy", line 198, in script call
    call _gl_test
  File "renpy/common/00gltest.rpy", line 440, in script
    with None
  File "game/script.rpy", line 20, in date_overlay
    if show_date:
NameError: global name 'show_date' is not defined

I'm flying blind because I'm in no way a programmer, and I'm not sure what might have changed between versions to make this code a problem. If anyone has any insight, it would be greatly appreciated, and if there's another more up-to-date code I need to be using, please let me know.