[NEW] devel/py-frozendict: Immutable dictionary implementation for Python

frozendict is an immutable wrapper around dictionaries that implements the
complete mapping interface. It can be used as a drop-in replacement for
dictionaries where immutability is desired.

WWW: https://github.com/slezica/python-frozendict

PR: 205914
Submitted by: Brendan Molloy <brendan+freebsd@bbqsrc.net>