need to update Function.php in BfastMag Pro theme.

Hi Raja,
I need to update Function.php file as suggested my Yoast support in our theme.

Could you please tell me that how can I update function.php for below code. I need to add below code in Function.php file.

function max_entries_per_sitemap() {
return 100;
}

add_filter( ‘wpseo_sitemap_entries_per_page’, ‘max_entries_per_sitemap’ );

Thanks.
Rahul Shrivastava