parameters in python built-in functions min() and sorted() -

i'm doing tasks on py.checkio.org, have meet exercise write own function min() , max().

i have read documentation function in official documentation , i'm surprised described parameters, like: min(iterable, *[, key, default])

i'm wondering construction *[, mean, strange, because *args , **kwargs clear, [,arg] clear. *[, strange, parameter mean?

p.s sorted() function has strange parameter asterisk: sorted(... *, ...) can mean?

the following applies python 3 (to op linked).

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the single star (*) in function definition of sorted denotes following named parameters must supplied keyword arguments ("keyword-only arguments", see pep 3102). means following won't work:

>>> sorted([1, 2, 3], lambda x: x) [...] typeerror: must use keyword argument key function 

instead must supply parameters via keyword arguments:

>>> sorted([1, 2, 3], key=lambda x: x) [1, 2, 3] 

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i'm not sure , *[, key, default] syntax shall denote (it's not valid python documentation purpose) think developers want express same thing, namely have provide parameters keyword arguments (because min , max can take arbitrary number of positional arguments way it).