How to use the west.log.err function in west

# Finally, run the command.
        try:
            if args.command in self.builtins:
                if self.mle:
                    self.handle_builtin_manifest_load_err(args)

                cmd = self.builtins.get(args.command, self.builtins['help'])
                cmd.run(args, unknown, self.topdir, manifest=self.manifest)
            else:
                self.run_extension(args.command, argv)
        except KeyboardInterrupt:
            sys.exit(0)
        except BrokenPipeError:
            sys.exit(0)
        except CalledProcessError as cpe:
            log.err(f'command exited with status {cpe.returncode}: '
                    f'{quote_sh_list(cpe.cmd)}', fatal=True)
            if args.verbose >= log.VERBOSE_EXTREME:
                log.banner('Traceback (enabled by -vvv):')
                traceback.print_exc()
            sys.exit(cpe.returncode)
        except ExtensionCommandError as ece:
            msg = f"extension command \"{args.command}\" couldn't be run"
            if ece.hint:
                msg += '\n  Hint: ' + ece.hint

            if args.verbose >= log.VERBOSE_EXTREME:
                log.err(msg, fatal=True)
                log.banner('Traceback (enabled by -vvv):')
                traceback.print_exc()
            else:
                tb_file = dump_traceback()

if args.version:
        print_version_info()
        sys.exit(0)

    # Set up logging verbosity before doing anything else, so
    # e.g. verbose messages related to argument handling errors
    # work properly.
    log.set_verbosity(args.verbose)

    if IN_MULTIREPO_INSTALL:
        set_zephyr_base(args)

    if 'handler' not in args:
        if IN_MULTIREPO_INSTALL:
            log.err('west installation found (in {}), but no command given'.
                    format(west_dir()))
        else:
            log.err('no west command given')
        west_parser.print_help(file=sys.stderr)
        sys.exit(1)

    return args, unknown

def manifest_rev_sha(project, stats, take_stats):
        # update() helper. Get the SHA for manifest-rev.

        try:
            if take_stats:
                start = perf_counter()
            return project.sha(QUAL_MANIFEST_REV)
            if take_stats:
                stats['get new manifest-rev SHA'] = perf_counter() - start
        except subprocess.CalledProcessError:
            # This is a sign something's really wrong. Add more help.
            log.err(f'no SHA for branch {MANIFEST_REV} '
                    f'in {project.name_and_path}; was the branch deleted?')
            raise

def check_force(self, cond, msg):
        '''Abort if the command needs to be forced and hasn't been.

        The "forced" predicate must be in self.args.forced.

        If cond and self.args.force are both False, scream and die
        with message msg. Otherwise, return. That is, "cond" is a
        condition which means everything is OK; if it's False, only
        self.args.force being True can allow execution to proceed.
        '''
        if not (cond or self.args.force):
            log.err(msg)
            log.die('refusing to proceed without --force due to above error')

def _check_force(self, msg):
        if not self.args.force:
            log.err(msg)
            log.die('refusing to proceed without --force due to above error')

def _check_force(self, msg):
        if not self.args.force:
            log.err(msg)
            log.die('refusing to proceed without --force due to above error')

def _handle_failed(self, args, failed):
        # Shared code for commands (like status, diff, update) that need
        # to do the same thing to multiple projects, but collect
        # and report errors if anything failed.

        if not failed:
            return
        elif len(failed) < 20:
            s = 's:' if len(failed) > 1 else ''
            projects = ', '.join(f'{p.name}' for p in failed)
            log.err(f'{self.name} failed for project{s} {projects}')
        else:
            log.err(f'{self.name} failed for multiple projects; see above')
        raise CommandError(1)