How to modify marker style in Pyplot?

I am using PyPlot to draw a plot. What are the parameters for the fill color, line, and size fo the markers?
I am using

myPlot = plot(col_x, col_y, linestyle = "none", marker = "o", color = "black")

but if I use color = white, the marker is not shown.
Thank you

I have found this solution:

myPlot = plot(aer_x, aer_y, linestyle = "none", marker = "o", color = "white",
    ms = 4, mec = "black")

Case closed.