def vformat(self, format_string, args, kwargs):
        """Override :meth:`string.Formatter.vformat` for character substitution in paths for Windows, see issue #84."""
        ret = super().vformat(format_string, args, kwargs)
        if platform.system() == 'Windows':
            ret = ret.replace(':', '\ua789').replace('<', '\ufe64').replace('>', '\ufe65').replace('\"', '\uff02')
            ret = ret.replace('\\', '\uff3c').replace('|', '\uff5c').replace('?', '\ufe16').replace('*', '\uff0a')
        return ret