I also add an to the value and a histogram which shows the difference between the two. Positive values mean that is expanding while negative values mean is contracting.
In true TradingView spirit, the author of this script has published it open-source, so traders can understand and verify it. Cheers to the author! You may use it for free, but reuse of this code in a publication is governed by House Rules. You can favorite it to use it on a chart.