[issue14117] Turtledemo: exception and minor glitches.

[Terry J. Reedy]

Change by Terry J. Reedy <tjreedy at udel.edu>:


----------
pull_requests: +7609
stage: needs patch -> patch review

_______________________________________
Python tracker <report at bugs.python.org>
<https://bugs.python.org/issue14117>
_______________________________________