[Python-Dev] Proposal: Allow any mapping after ** in calls

[Alexander Belopolsky]

Python allows arbitrary sequences after * in calls, but an expression
following ** must be a (subclass of) dict.  I believe * and ** should
be treated similarly and since f(*UserList(..)) is valid,
f(**UserDict(..)) should be valid as well.

Of course, I can work around this limitation by writing
f(**dict(UserDict(..))), but this is unnatural given that I don't have
to do f(*tuple(UserList(..))).

I have submitted a patch on SF that makes Python accept arbitrary
mappings after **.

See
<https://sourceforge.net/tracker/?func=detail&atid=305470&aid=1686487&group_id=5470>.