How does one ignore unexpected keyword arguments passed to a function?

As an extension to the answer posted by @Bas, I would suggest to add the kwargs arguments (variable length keyword arguments) as the second parameter to the function

>>> def f (a=None, **kwargs):
    print a


>>> dct2 = {"a":"Foo", "b":"Bar"}
>>> f(**dct2)
Foo

This would necessarily suffice the case of

1. to just ignore any keys that are not parameter names
2. However, it lacks the default values of parameters, which is a nice feature that it would be nice to keep