Check if a specific addon is enabled?

[SnowmanDK]

Is there a way to check for this?
I ask as I am trying to integrate support for Item Saver in my Bank Manager Revived.
Item Saver uses a global variable which I pull (ItemSaver_IsItemSaved(item.bag, item.slot)),
It returns 1 if the checked item is saved, otherwise nil.
I made that work fine, but when Item Saver is not enabled in AddOns, then I get a "function expected instead of nil" error.

So... I guess I need to make sure Item Saver is enabled in AddOns before even running this check.
Can this be done?