Fix bug where argument was ignored

[canyon289]

While the code works, the posterior argument is ignored and to a human it looks like a second non keyword argument is actually doing something when it isnt

@ColCarroll Out of curiosity why is an api where all non keyword arguments are ignored, except the first one preferred?

(obj, *_, group='posterior', coords=None, dims=None)

Before change

[ahartikainen]

I think instead of

(obj, *_, group='posterior', coords=None, dims=None)

it should be

(obj, *, group='posterior', coords=None, dims=None)

which will throw a TypeError exception.

[canyon289]

Fair point, not sure if the idea is to ignore extra arguments, or disallow extra arguments. The pattern is repeating in a couple other functions as well so I think its intentional and not a mistake. Just am curious about the reasoning behind it

[ColCarroll]

Sorry, I meant to do what Ari was suggesting, but messed up the pattern. Can fix tomorrow, unless you've got something ready!