Using child theme, replace hearts

So I just activated my child theme and want to replace the hearts and stuff so I’ve been using the code you guys have provided here. https://archived.seventhqueen.com/forums/topic/removereplace-the-love-hearts-in-site

I added all that code in the sweetdate child themefunctions.php but nothing changes.

When I add it to the parent themefunctions.php it works.

What am I doing wrong?

I added all the code in the line right after the PHP opening tag.

Thanks