Big problem after I changed the settings.php file

Hi,
I’d like to exclude some pages and posts from Link Copy.
I found a post from
https://www.ads-software.com/support/topic/how-do-i-exclude-some-pages-from-link-copy/
The post IDs of those posts I want to exclude are 6888/6886/6797 then I added these code below to settings.php file

global $post;   
$page = $post->ID();
if($page && in_array($page, array(6888, 6886, 6797))) {

/*The existing code inside the add_script function() */

}

But after uploading the settings.php file I changed to wp-content -> plugins -> add-link-to-copied-text.
My site is broke!
I have no idea if there is something wrong with what I changed to the settings.php file.
So,what I can do is uploading the original settings.php file to make everything right.
Although my site works well now after uploading the original settings.php file.
But I still want to exclude some pages and posts from Link Copy.
I’d like to figure out if what I changed to settings.php file is incorrect ?
Here is a screenshot of the settings.php file I added the code:

View post on imgur.com

I will appreciate your help with this situation.