This commit:
commit 8f6c452b5a4e50fbb55ff1d13328b392ad1fd416
Date: Sun Oct 15 22:48:42 2023 +0100
gdb: implement missing debug handler hook for Python
introduced a use of str.isascii(), which was only added in Python 3.7.
This commit switches to use curses.ascii.isascii(), as this was
available in 3.6.
The same is true for str.isalnum(), which is replaced with
curses.ascii.isalnum().
There should be no user visible changes after this commit.