Warning: strpos(): Empty needle

I’ve created a local site that’s the same as a live site. I’m using Generate Press and a child theme. I copied the functions file to the local site and now have this warning at the top of the pages on my local site:
Warning: strpos(): Empty needle in /app/public/wp-content/themes/generatepress_child/functions.php on line 100 There’s also a warning for line 107.

This is line 100 strtolower(get_permalink(ph_get_page_id( ‘search_results’ )))
and this is line 107 strtolower(get_permalink(ph_get_page_id( ‘search_results’ )))

I did a Google search but I really don’t understand the results.

Any idea how I get rid of the warning?

Thanks

I got rid of the warning.
First I deleted the function. The warning was gone.
Then I pasted the function back into the functions file. No warning. I have no idea why it worked or why there was a warning but it’s fine now.