How to add a single tick value to default ticks on an axis?

Hi!

I’d like to combine two things: a single tick value, and the default ticks on a y axis.

image

I can do either or, by writing figure.update_yaxes(tickvals=[average], ticktext['Average: ’ + str(average)]) and then I get the lefthand case above, or not doing it and then I get the righthand case.

Can you append to default ticks? Or maybe the default tick function can be re-used, modified and applied explicitly if one knows it?