Increase OOR Alpha/Fade Transparency for Raid Frames?

[Xancepants]

Hello All!
Was wondering if anybody could help with a bit of Lua code that can Increase the Alpha / Fade Transparency of the Blizzard Raid Frames, for raid members that are out of the 40yd Spell Range? Found a number of addons out there that can achieve this, but am trying to avoid DL'ing addons as much as possible.


I found this bit of Lua which does work, but it keeps throwing errors for some reason?

--[Change Raid Frame OOR Fade/Alpha Transparency]
hooksecurefunc("CompactUnitFrame_UpdateInRange",function(frame)
    local inRange,checkedRange = UnitInRange(frame.displayedUnit)
    if checkedRange and not inRange then
        frame.background:SetAlpha(0.3)
        frame:SetAlpha(0.3)
    else
        frame.background:SetAlpha(1)
        frame:SetAlpha(1)
    end
end)

And here is the error that Bug Sack is logging:

802x Custom Settings\Custom Settings.lua:602: attempt to index field 'background' (a nil value)
Custom Settings\Custom Settings.lua:602: in function <Custom Settings\Custom Settings.lua:596>

Any help is appreciated, thank you in advance!