Display Icons in wg.grid Column Header

I have searched through the forum and found some very old code to display a triangle in a header cell to indicate that the column is sorted in a particular direction. The problem is that its obviously written for a much older version of wxPython and also Python 2. I am using wxPython 4.0.0.b1 and it seems to be a non-trivial job to convert it as I don’t have that much experience with Python or indeed the wxPython framework.

Please - can someone contribute a code sample to show how to load an icon from an icon file (or resource file) and display it in one of the column headers of a grid?

Thanks,

Eric