change mod

[Broker]

Hello
trying to change how the mod works Filter Select

trying to make a function of adding a new unit to a group, not creating a new group.

but not working

if Filters[group] == nil then Filters[group] = {}

full code

local Filters = {}

function AddFilterSelection(group)
	local SelectedUnits = GetSelectedUnits()
	local Names = {}
		
	
	-- I add this
	if Filters[group] == nil then Filters[group] = {}
	
	-- i comment this	
	--Filters[group] = {}
	

	
	for _,unit in SelectedUnits do
		local id = unit:GetEntityId()
		local bp = unit:GetBlueprint()
		--LOG(repr(bp))
		if not isInTable(Filters[group],bp.BlueprintId) then
			Filters[group][id] = bp.BlueprintId
			Names[id] = TechCategoryList[bp.TechCategory]..LOC(bp.Description)
			--Names[id] = bp.General.UnitName
		end
	end
	message = 'Filter contains: '
	for _,unitName in Names do
		message = message..unitName..', '
	end
	print(message)
	--PrintText(message,28,"ff9161ff",1, 'centerbottom')
end