Can't declare a key to a module after it was created because of the types

Hey! I’m currently learning how to use Types in Roblox(Luau), so I decided to make a module for my game with Types, but it seems I can’t declare a variable or a function of the module after it was created, here’s the image:

Module Code:

--// VARIABLES
local ModulesFolder:Instance = script.Parent
--// IMPORTS
local TypesModule:{} = require(ModulesFolder:FindFirstChild("Types"))
--// MODULE
local BaseClassModule:TypesModule._BaseClass = {}
--// MODULE FUNCTIONS
function BaseClassModule.new(anchorPoints:{Instance}, controlPoints:{Instance}): TypesModule._BaseObject
	
end
--// RETURNS
return BaseClassModule

TypesModule Code:

--// MODULE
local TypesModule:{} = {}
--// EXPORTS
export type _MainModule = {
	BaseClass:_BaseClass,
	Types:{}
}
export type _BaseClass = {
	new: ({Instance}, {Instance}) -> _BaseObject
}
export type _BaseObject = {
	GetAnchorPoints: () -> {Instance},
	GetControlPoints: () -> {Instance},
}
--// RETURNS
return TypesModule

I would be grateful for your help!