def error(msg, details=None, *args, **kwargs):
msg = '<STR_LIT>'.format(red(KO), white(msg))<EOL>if details:<EOL><INDENT>msg = '<STR_LIT:\n>'.join((msg, safe_unicode(details)))<EOL><DEDENT>echo(format_multiline(msg), *args, **kwargs)<EOL>
Display an error message with optionnal details