I need a couple of lines of PHP written...

PLEASE READ BEFORE BIDDING!!!!! I have a WooCommerce store with lots of products. I also have an XML file with the current stock status and I am using WP all import to import the stock status to my products. The XML file has stock statuses listed as "yes" or "no" but WP all import needs to read this as "instock" or "outofstock". I need an str_replace function written that will tell wp all import to read "yes" as instock and "no" as outofstock. Please be aware that I can not release payment until the code is confirmed as working from my end. Thanks