Making immutable instances

[Paul Rubin]

"Giovanni Bajo" <noway at sorry.com> writes:
> > However, when you prevent a client from adding an attribute, you're
> > not merely making your objects immutable, you're making them
> > static.

No I don't believe that.  If an object is immutable, then
obj.serialize() should return the same string every time.  If you can
add attributes then the serialization output will become different.