Animation duration paused for emphasis

Is it possible to alter the durations by frame?

I would like to pause. my animation on a specific frame that I would also like to annotate. I have drilled through the slider & update menu buttons to no avail. updatemenus will extend the length of the entire animation, but does not respect the โ€˜durationโ€™ of the frame I wish to annotate.

fig.layout.sliders[0]['steps'][24]['args'][1]['frame']['duration'] = 1500
fig.layout.sliders[0]['steps'][24]['args'][1]['transition']['duration'] = 1500
fig.layout.updatemenus[0].buttons[0].args[1]['frame']['duration'] = 500```