in settings app, go to pythonista, and try enabling safemode.
if that doesnt work, you can try typing pythonista:// into safari.
barring that, try an uninstall/reinstall
thank you. I didn't know that there's a safemode.
before seeing this, I found that I can use this App from share extension console,
and then I deleted last edited file, which contains only two lines:
groups = contacts.get_all_groups()
and then the App works again.
the strange thing is that these lines are normal script lines.
now I add back these two lines it still works.
something very strange mush happened.