My trick is searching out the string that builds the expression. It is unique, because Maya will not allow you to create two expressions controlling the same attribute like "ls.rotateY". If I need to change an expression in run time, I just search it out and edit it. If I want to see the expression as it appears, I just copy it to the script editor and print it. This is a key method used in the Walkerman program I created, it allows me to change the gaits and control the hands in runtime.