def error_mode(self):
        """error mode: enable only errors; no reports, no persistent"""
        self._error_mode = True
        self.disable_noerror_messages()
        self.disable("miscellaneous")
        if self._python3_porting_mode:
            self.disable("all")
            for msg_id in self._checker_messages("python3"):
                if msg_id.startswith("E"):
                    self.enable(msg_id)
            config_parser = self.cfgfile_parser
            if config_parser.has_option("MESSAGES CONTROL", "disable"):
                value = config_parser.get("MESSAGES CONTROL", "disable")
                self.global_set_option("disable", value)
        else:
            self.disable("python3")
        self.set_option("reports", False)
        self.set_option("persistent", False)
        self.set_option("score", False)
error mode: enable only errors; no reports, no persistent