In MNELAB, I would like my raw.plot window to not close if the user hits the Esc key. Previously, I used the following hack which worked for matplotlib < 3:

 try:
    key_events = fig.canvas.callbacks.callbacks["key_press_event"][8]
except KeyError:
    pass
else:  # this requires MNE >=0.15
    key_events.func.keywords["params"]["close_key"] = None

Of course this was bound to fail, and with matplotlib >= 3 key_events is now a matplotlib.cbook._StrongRef object, whereas previously it used to be a matplotlib.cbook._BoundMethodProxy object. Of course private methods can change at anytime, but does anyone know either how to make the old hack work again, or better yet how to modify/delete existing callbacks?