Fisher Transform MTF

study(title="Fisher Transform MTF", shorttitle="MTF Fisher" )
resCustom = input(title="Timeframe", type=resolution, defval="60" )
len = input(34, minval=1, title="Length")
high_ = highest(hl2, len)
low_ = lowest(hl2, len)
round_(val) => val > .99 ? .999 : val < -.99 ? -.999 : val
value = round_(.66 * ((hl2 - low_) / max(high_ - low_, .001) - .5) + .67 * nz(value[1]))
fish = .5 * log((1 + value) / max(1 - value, .001)) + .5 * nz(fish[1])
fish1 = security(tickerid, resCustom,fish)
plot(fish1, color=blue, title="Fisher",style=histogram)
hline(0, color=orange)