/invsee working?

is /invsee actually working?
I tried using it on a player and it gives me an error:

> Error occurred while executing command: Method net/minecraft/entity/player/EntityPlayerMP.openInventory(Lorg/spongepowered/api/item/inventory/Inventory;Lorg/spongepowered/api/event/cause/Cause;)V is abstract

using spongeforge-1.8.9-1763-4.1.0-BETA-1218

This is not implemented yet, please wait.