attempt to call a nil value (global 'tablelength')

elseif roomType == RoomType.ROOM_DEVIL then
				local devilPool = {67,113,163,187,268,269,275,360,412,417,431,433,468,519}
				for z = 1, #entities do
					local entity = entities[z]
					if entity.Type == EntityType.ENTITY_PICKUP
					and entity.Variant == PickupVariant.PICKUP_COLLECTIBLE then
						-- look for a familiar from the devil pool
						for x = 1, tablelength(devilPool), 1 do
							if entity.SubType == devilPool[x] then
								local itemRng = player:GetCollectibleRNG(devilPool[x])
								local bumRoll = itemRng:RandomInt(100)
								if bumRoll < bumChance then
									-- spawn a dark bum
									entity:ToPickup():Morph(EntityType.ENTITY_PICKUP, PickupVariant.PICKUP_COLLECTIBLE, CollectibleType.COLLECTIBLE_DARK_BUM, true)
								end
							end
						end
					end
				end

			end