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 doesn’t seem to be an easy way to simply display some text that is not tied to the x or y axis…in my case, in the upper left.

Any help would be appreciated.