Re: trellis attrs

Thank you very much for your explanations.

> Please note that 'prevs' is *not* a "class variable".=A0 It's a descripto=
r.
> That is, Step.prevs is a descriptor object, but someStep.prevs (where
> someStep is an instance of Step) will be a distinct trellis.Set() instanc=
e,
> unless overridden when created (e.g. via "someStep=3DStep(prevs=3D...)").

I never read about python descriptors before, and even didn't know
such a thing exists. Do you perhaps of one particular book/source that
can be of help in this direction?

Nicky


>