pine script - Need help to use resolution

Question

I am getting "cannot use a mutable variable as an argument of the security function " this error for bg color. can anyone please help me to solve it. Thanks

study("ADX")
len = input(title="Length", type=input.integer, defval=20)  
avg = input(title="SMA", type=input.integer, defval=20) 

TrueRange = max(max(high - low, abs(high - nz(close[1]))), abs(low - nz(close[1])))
DirectionalMovementPlus = high - nz(high[1]) > nz(low[1]) - low ? max(high - nz(high[1]), 0) : 0
DirectionalMovementMinus = nz(low[1]) - low > high - nz(high[1]) ? max(nz(low[1]) - low, 0) : 0

SmoothedTrueRange = 0.0
SmoothedDirectionalMovementPlus = 0.0
SmoothedDirectionalMovementMinus = 0.0

SmoothedTrueRange := nz(SmoothedTrueRange[1]) - nz(SmoothedTrueRange[1]) / len + TrueRange
SmoothedDirectionalMovementPlus := nz(SmoothedDirectionalMovementPlus[1]) - nz(SmoothedDirectionalMovementPlus[1]) / len + DirectionalMovementPlus
SmoothedDirectionalMovementMinus := nz(SmoothedDirectionalMovementMinus[1]) - nz(SmoothedDirectionalMovementMinus[1]) / len + DirectionalMovementMinus


DIPlus = SmoothedDirectionalMovementPlus / SmoothedTrueRange * 100
DIMinus = SmoothedDirectionalMovementMinus / SmoothedTrueRange * 100

res = input(title="Resolution", type=input.resolution, defval="5")
s1 = security(syminfo.tickerid, res, DIPlus, gaps=true)
s2 = security(syminfo.tickerid, res, DIMinus, gaps=true)
bgcolor(s1>s2?color.new(color.green,70):s1<s2?color.new(color.red,70):na,title="Adx bg")

Answer 1

Waitting for answers