2016-07-29 0:06 GMT+02:00 Guido van Rossum firstname.lastname@example.org:
I think you misunderstand the distinction between immutable and read-only. MappingProxyType is read-only -- you cannot modify the underlying dict through the proxy. But it's not immutable -- if the underlying dict is changed directly (e.g. by assignment to a class attribute) the proxy is changed too.
Oh right. That's why I'm not a big fan of MappingProxyType :-)
It reminds me that I wrote a frozendict PEP which was rejected :-) https://www.python.org/dev/peps/pep-0416/