Fatal error after adding Mage.php path

I got this error after installing and adding my Mage.php path.

Fatal error: Cannot redeclare __() (previously declared in /home/basement/public_html/sneaker-news/wp-includes/l10n.php:146) in /home/basement/public_html/app/code/core/Mage/Core/functions.php on line 96

Any fix for this issue. I tried unistalling the plugin and re-installing and now when I try to go to the settings all it shows is this error message.

Thanks

https://ww.wp.xz.cn/plugins/magento-wordpress-integration/