[pstricks] Testing key-value pairs and \psset

[Hensh, Richard]

Suppose that

\define at key[psset]{pNode}{PointName}{\edef\psk at PointName{#1}}%

How do I test for each of the following?

        \psset{PointName={}} or \psset{PointName=}

        versus

        \psset{}

I've tried looking at the pstricks packages but I can't figure out what anyone is doing along these lines.

Thanks
ricky