"Userdata value" for Tool.Equipped?

Hi, I'm trying to do simple stuff with guns. Here, when the player equips the gun, all the stuff happens. However, studio says: Pistol.LocalScript:12: attempt to call field 'Equipped' (a userdata value)

Here's the LocalScript:

--defining things
local MaxAmmo = script.Parent.ClipSize.Value
local Ammo = MaxAmmo
local Reloading = false
local reloadTime = script.Parent.ReloadTime
local gun = script.Parent

--Cursor
gun.Equipped(function(Mouse)
    Mouse.Icon = "rbxasset://textures://GunCursor.png"
    script.Parent.Activated:Connect(function()
        if Ammo>0 then  
            Ammo=Ammo-1
        elseif Reloading == false then
            Reloading = true
            Mouse.Icon = "rbxasset://textures://GunWaitCursor.png"
            wait(reloadTime.Value)
            Reloading = false
            Mouse.Icon = "rbxasset://textures://GunCursor.png"
        end
        print(Ammo)
    end)
end)

Any help is appreciated!