Internal Program Version: cycler  0.12.1

When plotting more than one line it is common to want to be able to
cycle over one or more artist styles. For simple cases than can be
done with out too much trouble.

However, if you want to do something more complicated, the plotting
logic can quickly become very involved. To address this and allow
easy cycling over arbitrary kwargs the Cycler class, a composable
kwarg iterator, was developed.

https://github.com/matplotlib/cycler