STARC Bands Backtest

A type of technical indicator that is created by plotting two bands around
a short-term simple moving average (SMA) of an underlying asset's price.
The upper band is created by adding a value of the average true range
(ATR) - a popular indicator used by technical traders - to the moving average.
The lower band is created by subtracting a value of the ATR from the SMA.
STARC is an acronym for Stoller Average Range Channels. The indicator is
named after its creator, Manning Stoller.

You can change long to short in the Input Settings
WARNING:
- For purpose educate only
- This script to change bars colors.