How to use the mackup.utils.error function in mackup

def create_mackup_home(self):
        """If the Mackup home folder does not exist, create it."""
        if not os.path.isdir(self.mackup_folder):
            if utils.confirm(
                "Mackup needs a directory to store your"
                " configuration files\n"
                "Do you want to create it now? <{}>".format(self.mackup_folder)
            ):
                os.makedirs(self.mackup_folder)
            else:
                utils.error("Mackup can't do anything without a home =(")

def _warn_on_old_config(self):
        """Warn the user if an old config format is detected."""
        # Is an old setion is in the config file ?
        old_sections = ["Allowed Applications", "Ignored Applications"]
        for old_section in old_sections:
            if self._parser.has_section(old_section):
                error(
                    "Old config file detected. Aborting.\n"
                    "\n"
                    "An old section (e.g. [Allowed Applications]"
                    " or [Ignored Applications] has been detected"
                    " in your {} file.\n"
                    "I'd rather do nothing than do something you"
                    " do not want me to do.\n"
                    "\n"
                    "Please read the up to date documentation on"
                    "  and migrate"
                    " your configuration file.".format(MACKUP_CONFIG_FILE)
                )