for example
http://docs.python.org/3/library/itertools.html#itertools.permutations

has same description and it's a keyword

compare
"itertools.tee(iterable, n=2)"
"itertools.permutations(iterable, r=None)"


>>> itertools.permutations('abc')
<itertools.permutations object at 0x7ff563b17230>
>>> itertools.permutations('abc', r=2)
<itertools.permutations object at 0x7ff563b17290>
>>> 
>>> 
>>> itertools.tee('abc')
(<itertools._tee object at 0x7ff563a995f0>, <itertools._tee object at 0x7ff563a99638>)
>>> itertools.tee('abc', n=2)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: tee() takes no keyword arguments
>>>