keywordarg.py

>>> def f(*, a, b):
...     print(a, b)
...
>>> f(1, 2)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: f() takes 0 positional 
           arguments but 2 were given
>>> f(a=1, b=2)
1 2
>>>