`axis_ticks` in `theme` not changing color

[gopalpenny]

I can't get the theme element axis_ticks to change the color of the ticks. For example, the following code allows me to change the size of the ticks but not the color. I've tried with both the color and colour arguments. I'm using plotnine version 0.8.0. The following code reproduces the issue for me.

import plotnine as p9

# panel gridlines are red and with width 3 (good)
# axis ticks change to width 3 but the color remains black
(p9.ggplot() + 
    p9.geom_point(p9.aes(x = 1, y = 1), size =5) + 
    p9.theme(axis_ticks = p9.element_line(color = 'red', size = 3),
             panel_grid_major = p9.element_line(color = 'red', size = 3))) 

Thanks for the support. The plotnine package has made my transition from R to python so much easier.