How do I check if an entity is an instance of the EntityLiving class?

I'm making a mod for a Minecraft challenge called 'Minecraft, but random mobs spawn everytime you kill a mob'. So I made a mod workspace and added a procedure which triggers when an entity dies. I need to make sure that the died entity extends from the EntityLiving class. How do I check if an entity is an instance of the EntityLiving class? Is there any procedures for this?