Functions.php missing

I added a bit of code to a child theme of Meris Pro in the functions.php at the very end https://ww.wp.xz.cn/support/topic/sort-pages-by-date-in-admin-by-default

and as soon as I did I got this in both the child theme and regular theme.

Fatal error: Cannot redeclare magee_theme_register_required_plugins() (previously declared in /homepages/18/d374853500/htdocs/clickandbuilds/likiardopoulos/wp-content/themes/meris-child-01/functions.php:69) in /homepages/18/d374853500/htdocs/clickandbuilds/likiardopoulos/wp-content/themes/meris/functions.php on line 125

and I cannot seem to replace it with the downloaded functions.php (I am using Orbisius Theme Editor)

Please Help me the Whole site is down because of it.