def foo(a, b, **kwds):
    print a, b
    for key, value in kwds.iteritems():
        print key, '-->', value
foo(1, 2, pippo=3, pluto=4)
foo(pippo=3, a=1, b=2, pluto=4)
d = {'pippo': 3, 'a': 1}
foo(pluto=4, b=2, **d)