Ben's right regarding the facts. Here's my examples.
Python 3.6.9 (default, Jul 17 2020, 12:50:27)
>>> def foo(*argv, **kwargs): return argv, kwargs
>>> foo(*'ab', x=1, y=2, *'cd', z=3)
(('a', 'b', 'c', 'd'), {'x': 1, 'y': 2, 'z': 3})
Python 2.7.17 (default, Jul 20 2020, 15:37:01)
>>> def foo(*argv, **kwargs): return argv, kwargs
>>> foo(*'ab', x=1, y=2, *'cd', z=3)
SyntaxError: invalid syntax
Also, in Python 3.6.9
>>> foo(**{}, *())
is a SyntaxError, but
>>> foo(x=1, *())
is not.
I think the change happened as a result of
PEP 448 -- Additional Unpacking Generalizations
https://www.python.org/dev/peps/pep-0448/
It reads, in part,
> Function calls may accept an unbounded number of * and ** unpackings.
> There will be no restriction of the order of positional arguments with
> relation to * unpackings nor any restriction of the order of keyword
> arguments with relation to ** unpackings.
Ben also asked: This is against the understanding of unpacking, is this
intentional?
I was surprised at the unpacking behaviour. My first thought was that Ben
had made some mistake regarding the facts. So I made the check you see
above.
--
Jonathan
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