Php File Needs Decrypting

Hi,
I have 1 php file that I need to get decrypted.
I am not sure how it was encoded, as my former business partner done it all.

File starts with

<?php if(!function_exists("agF1gTdKEBPd6CaJ")) { function agF1gTdKEBPd6CaJ($ekV4gb3DGH29YotI)