Attached patch (issue2516poc.diff) presents proof-of-concept code which 
changes the problematic reporting as follows:

>>> a.f(1,2)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: <A object>.f() takes exactly 0 arguments (2 given)

More effort is needed to make this patch ready: support default/keyword 
arguments, respect English grammar in 1-argument case, etc.  Before I do 
that, however, I would like to hear that this is a worthwhile fix and 
that I've chosen the right place in the code to implement it.