[Python-3000] Immutable bytes type and dbm modules

["Martin v. Löwis"]

>> If that is not acceptable, please tell me how else
>> to fix the dbm modules.
> 
> By fixing the code that uses them?

I don't know how to do that. All implementation strategies I
can think of have significant drawbacks.

> By using str8 (perhaps renamed to
> frozenbytes and certainly stripped of its locale-dependent APIs)?

Ok. So you could agree to a frozenbytes type, then? I'll add one,
reusing the implementation of the bytes object.

If that is done:

a) should one of these be the base type of the other?
b) should bytes literals be regular or frozen bytes?
c) is it still ok to provide a .freeze() method on
   bytes returning frozenbytes?
d) should unicode.defenc be frozen?
e) should (or may) codecs return frozenbytes?

Regards,
Martin