All of the Ehlers indicators that are based on digital signal processing are available through his book "Rocket Science for Traders" and through many articles in Stock & Commodities which is in love with his work. If you take code from the book you are going to spend a lot of time debugging the many errors. A much better approach is to find public domain working code that can be found at:
https://www.ta-lib.org/ which has most of Ehlers code with better documentation.
You can also get a demo account through TradingView.com and they also have most of his indicators available and you can test many of the 'overbought/oversold' indicators against each other very easily within about 30 or 40 minutes.
Several years ago I was trying to find the 'most perfect' indicator and I heard this interview of scott billington suggest that the indicator used to define trend following or mean-revering is not as important as the understanding of what you want to do. Link to the interview is below...
If you question this, get a demo account of TradingView.com, place CCI, RSI, and any of the mean-reverting Ehlers indicators all on a page. You can tweak the parameters of the indicator to achieve the same result. What you are trying to do is more important than the means you use to code the indicator. The information in your streaming data is the same.
Instead of CCI,RSI, and Ehlers I would also add 'TrendStrengthIndicator' which I like because it has a triple smoothed moving avg that can copy just about any mean-reverting indicator.
All of the source code for the Ehlers indicators and TrendStrength are visible on the TradingView application.
A good 'best of the art' baseline can also be found at:
http://jurikres.com/
Use jurikres indicators as the baseline and see how close you can get with TrendStrengthIndicator.... Does your trading results change if you switch indicators? Why?
Good luck,