How do I use debounce in userinputservice?

I've run in to an issue with UserInputService:

local player = game.Players.LocalPlayer
local mouse = player:GetMouse()
local OpenDoor = game:GetService("ReplicatedStorage").OpenDoor
local UIS = game:GetService("UserInputService")
UIS.InputBegan:connect(function(input)
    if input.KeyCode == Enum.KeyCode.E then
        if mouse.Target then
            OpenDoor:FireServer(mouse.Target)
        end
    end
end)

This works fine^ But when I try and put a debounce (so players dont spam it) it breaks, this is how I did the debounce:

local player = game.Players.LocalPlayer
local mouse = player:GetMouse()
local OpenDoor = game:GetService("ReplicatedStorage").OpenDoor
local UIS = game:GetService("UserInputService")
debounce = true
UIS.InputBegan:connect(function(input)
    if debounce == true then
        debounce = false
        if input.KeyCode == Enum.KeyCode.E then
        if mouse.Target then
            OpenDoor:FireServer(mouse.Target)
            debounce = true
        end
    end
    end
    
end)

Theres no errors or anything, it just doesn't work.