@Alain… In surface.py > AddSrfPt() the docstring says
Creates a new surface from either 3 or 4 control points.
points = list of either 3 or 4 control points
The identifier of the new object if successful.
None if not successful, or on error.
“control points” in this case should actually be “corner points”
This is the help item that shows up in bottom panel in the the script editor. The actual Help file is correct.