Check for funny characters with a regexp

[Gribouillis]

The problem is that I and S belong to the uppercase version of the character sequence

>>> s = "ā㥹ĆćČčĎďĐđēĕĖėęěĞğġīįİıĽľŁłŃńņňŋŌōőŒœŕřŚśŞşŠšŢţťŧũūŮűųŹźŻżŽžſ"
>>> s.upper()
'ĀĂĄĄĆĆČČĎĎĐĐĒĔĖĖĘĚĞĞĠĪĮİIĽĽŁŁŃŃŅŇŊŌŌŐŒŒŔŘŚŚŞŞŠŠŢŢŤŦŨŪŮŰŲŹŹŻŻŽŽS'
>>> 'I' in s.upper()
True
>>> 'S' in s.upper()
True

You could perhaps work without the case insensitive regex flag. It would be a good idea to compare with what Perl tells you about the uppercase version of the sequence.