Adding text to upper left of each subplot...(python)

I have a financial chart which has a bunch of indicators as subplots. The main plot along w/ the subplot can have multiple time series displayed. I would like to display in each of those subplots the last values of any series that are plotted on that subplot, in the upper left, Similar to this:

Surprisingly, this is proving to be rather difficult. While i can find documentation to display annotations, and while i can display an annotation at the very top left of the figure, there doesnโ€™t seem to be an easy way to simply display some text that is not tied to the x or y axisโ€ฆin my case, in the upper left.

Any help would be appreciated.