when looking at retention graphs it would useful (to me, at least) to be able to plot the time trend of retention for multiple months at a time, just like with distribution plots; for example, I'd like to see retention trends for month 1 through 5, and they would show up as 5 time graphs where the x index is the retention cohort and the y axis is the retention percent for that cohort on that specific month (currently you can only do one line at a time)