is None or == None ?

[Mel]

Alf P. Steinbach wrote:
> Note that the object implementation's complexity doesn't have to affect to
> any other code since it's trivial to provide abstract accessors (even
> macros), i.e., this isn't part of a trade-off except if the original
> developer(s) had limited
> resources  --  and if so then it wasn't a trade-off at the language design
> level but a trade-off of getting things done then and there.

But remember what got us in here: your belief (which followed from your 
assumptions) that computing `is` required testing the object types.  You 
might optimize out the "extra indirection" to get an object's value, but 
you'd need the "extra indirection" anyway to find out what type it was 
before you could use it.

	Mel.