request for help with small problem with cool indicator to plot span of swings

[Kicks.Spin]

Here is a cool indicator to plot the span of up & down swings. but there is an error in the onbar update: "Error on calling 'OnBarUpdate' method on bar 18: Object reference not set to an instance of an object." this is going to be easy for someone. what did id miss? thanks & feel free to use this if it helps.

[s.kinra]

Hello Licks.Spin,
You missed double series in DataLoaded. Add below in DataLoaded:

swinghighspan = new Series<double>(this);
swinglowspan = new Series<double>(this);

You haven't defined any plots so don't expect it on charts, print should work fine. Hope it helps!