Creating a clipping plane flipped?

Hi,

If this:

import rhinoscriptsyntax as rs

rs.AddClippingPlane( rs.WorldXYPlane(), 5.0, 3.0 )

creates a clipping plane clipping objects from below, how can I create a flipped one mirrored to this one to clip them from above.

Apparently mirror is a solution but how to initially create it flipped?

Thanks

Invert (flip) the plane first…?