fill-the-blanks: Error message in cards where "(?<!)" is cloze deleted

[ulissesAlmeidaJr]

It happens after I hit the show answer button.

Example of card:

{{c1::(?<!)}}

Error Message:

Error
An error occurred. Please start Anki while holding down the shift key, which will temporarily disable the add-ons you have installed.
If the issue only occurs when add-ons are enabled, please use the Tools > Add-ons menu item to disable some add-ons and restart Anki, repeating until you discover the add-on that is causing the problem.
When you've discovered the add-on that is causing the problem, please report the issue to the add-on author.
Debug info:
Anki 2.1.54 (b6a7760c) Python 3.9.10 Qt 6.3.1 PyQt 6.3.1
Platform: Linux
Flags: frz=True ao=True sv=2
Add-ons, last update check: 2023-01-14 09:45:55
Add-ons possibly involved: ⁨Fill the blanks - Multiple typecloze support, Image Occlusion Enhanced for Anki 21⁩

Caught exception:
Traceback (most recent call last):
File "aqt.webview", line 568, in handler
File "/home/junior/.local/share/Anki2/addons21/1933645497/handler.py", line 283, in _onFillBlankAnswer
reviewer._showAnswer()
File "decorator", line 232, in fun
File "anki.hooks", line 89, in decorator_wrapper
File "anki.hooks", line 86, in repl
File "/home/junior/.local/share/Anki2/addons21/1374772155/main.py", line 278, in on_show_answer
return _old(self)
File "aqt.reviewer", line 402, in _showAnswer
File "aqt.reviewer", line 332, in _mungeQA
File "aqt.reviewer", line 548, in typeAnsFilter
File "decorator", line 232, in fun
File "anki.hooks", line 89, in decorator_wrapper
File "anki.hooks", line 86, in repl
File "/home/junior/.local/share/Anki2/addons21/1933645497/handler.py", line 96, in
lambda _, buf, _old: self.typeAnsAnswerFilter(buf, _old), "around")
File "/home/junior/.local/share/Anki2/addons21/1933645497/handler.py", line 235, in typeAnsAnswerFilter
result = re.sub(r'<span class="?cloze\s*"?(\s*data-ordinal="\d\d?")?>%s' % html.escape(field.value),
File "re", line 210, in sub
File "re", line 304, in _compile
File "sre_compile", line 764, in compile
File "sre_parse", line 948, in parse
File "sre_parse", line 443, in _parse_sub
File "sre_parse", line 823, in _parse
re.error: unknown extension ?& at position 52

Caught exception:
Traceback (most recent call last):
File "aqt.webview", line 568, in handler
File "aqt.reviewer", line 730, in _onTypedAnswer
File "decorator", line 232, in fun
File "anki.hooks", line 89, in decorator_wrapper
File "anki.hooks", line 86, in repl
File "/home/junior/.local/share/Anki2/addons21/1374772155/main.py", line 278, in on_show_answer
return _old(self)
File "aqt.reviewer", line 402, in _showAnswer
File "aqt.reviewer", line 332, in _mungeQA
File "aqt.reviewer", line 548, in typeAnsFilter
File "decorator", line 232, in fun
File "anki.hooks", line 89, in decorator_wrapper
File "anki.hooks", line 86, in repl
File "/home/junior/.local/share/Anki2/addons21/1933645497/handler.py", line 96, in
lambda _, buf, _old: self.typeAnsAnswerFilter(buf, _old), "around")
File "/home/junior/.local/share/Anki2/addons21/1933645497/handler.py", line 235, in typeAnsAnswerFilter
result = re.sub(r'<span class="?cloze\s*"?(\s*data-ordinal="\d\d?")?>%s' % html.escape(field.value),
File "re", line 210, in sub
File "re", line 304, in _compile
File "sre_compile", line 764, in compile
File "sre_parse", line 948, in parse
File "sre_parse", line 443, in _parse_sub
File "sre_parse", line 823, in _parse
re.error: unknown extension ?& at position 52