Am 03.10.2018 um 20:46 schrieb Anders Hovmöller:

Chris' problem isn't an actual problem though. Its just a few sentences in a PEP. It might be a problem for other python implementations but I'm gonna put say 100 dollars on that it's not actually so. Pypy, jython, ironpython, who else? Without looking I'm betting they have the same implementation detail. 

I tried
Python 2.7.10 (default, Jul 14 2015, 19:46:27)
[GCC 4.8.2] on linux
on and it says:
   def f(a): 
..   print(a)
Traceback (most recent call last):
  File "python", line 1, in <module>
TypeError: f() got an unexpected keyword argument 'a+1'

Does CPython count as "other python implementation"?