InventoryItem Class/Type Doesnt Exist

[iMaCHVFX]

Im trying to follow the "tutorial" in the wiki, but when you get to "add item to inventory" part of it

https://github.com/expressobits/inventory-system/wiki/Inventory-Node#Add-items-to-inventory

you're thrown the error Parse Error: Parse Error: Could not find type "InventoryItem" in the current scope

i followed the tutorial in the wiki 1:1 and it just doesnt work

i looked through the addon files and i couldnt find a single thing referring to "InventoryItem" the addons file structure also looks ENTIRELY different from the tutorials