Forwarding keyword arguments from one function to another

[Albert Hopkins]

On Sun, 2009-02-22 at 12:09 -0800, Ravi wrote:
> I am sorry about the typo mistake, well the code snippets are as:
> 
> # Non Working:
> 
> class X(object):
>   def f(self, **kwds):
>   print kwds
>   try:
>     print kwds['i'] * 2
>   except KeyError:
>     print "unknown keyword argument"
>     self.g("string", kwds)
> 
>   def g(self, s, **kwds):
>     print s
>     print kwds
> 
> if __name__ == "__main__":
> x = X()
> x.f(k = 2, j = 10)
> 
> 
> # Working One
> 
> class X(object):
>   def f(self, **kwds):
>     print kwds
>     try:
>       print kwds['i'] * 2
>     except KeyError:
>      print "unknown keyword argument"
>    self.g("string", **kwds)
> 
> def g(self, s, **kwds):
>   print s
>   print kwds
> 
> if __name__ == "__main__":
> x = X()
> x.f(k = 2, j = 10)

Same reasoning, though admittedly the error text is misleading.

This example can be simplified as:

def foo(x, **kwargs):
    pass

>>> foo(1, {'boys': 5, 'girls': 10}) 
==> TypeError: foo() takes exactly 1 argument (2 given)

Again misleading, but the argument is the same (no pun intended).

However the following would have worked:

>>> foo(1, **{'boys': 5, 'girls': 10})

or 

>>> foo(1, boys=5, girls=10)