FFI How to add values to a $ list?

Using the FFI how do I add, lets say, an IP address to a list so that a filter like `"ip.src not in $bad_list"` will work? I've looked through the code and I can't seem to figure out how to do it. I did some examples of using lists for the lhs for like cookies etc. but this is not what I'm trying to do.

Any help is greatly appreciated!

Thanks!