[VANILLA] Possibility to detect mob immunity ?

Hello again, 

Is it possible to add a way to to detect which mod is immune to some spell effect ?

For exemple, For quest "Mossy Tumors" you need tu kill several "Timberling Mire Beast". Those mobs are immune to nature damage.

So with my hunter, when the bot want to trigger Serpent Sting, the debuff "Serpent Sting" isn't applyed. As I check the existence of the buff to move on to the next spell, it fails to find the buff and, as a result, it spams Serpent Sting shot on this mob.

If an IsImmune condition might exist it would bypass this spell.

I also know it could be usefull for other spell from other classes.

Best Regards