In the official doc of 2. Built-in Functions — Python 3.6.5
sorted(iterable, *, key=None, reverse=False):
Return a new sorted list from the items in iterable. Has two optional arguments which must be specified as keyword arguments.
The docs do not mention the *, what's it's function here?
There exist not such a symbol * in the previous version as sorted(iterable[, key][, reverse])
