Warning message in plugin page.

Hello.

I found this message in the admin page once updated to 1.9 from the previous version, instead of the usual “WP User Avatar” title:

Warning: _() expects exactly 1 parameter, 2 given in /home/mhd-01/www.mysite.url/htdocs/wp-content/plugins/wp-user-avatar/includes/wpua-options-page.php on line 16

If I change that line from
$wpua_options_page_title = _('WP User Avatar', 'wp-user-avatar');
to
$wpua_options_page_title = _('WP User Avatar');
the message disappear.

Maybe it’s a small bug, however, is this the correct fix?
Thanks.

https://ww.wp.xz.cn/plugins/wp-user-avatar/