def funkce(a,b=5,*args):
    print 'a:',a
    print 'b:',b
    print args


>>> funkce(8)
a: 8
b: 5
()

>>> funkce(8,555)
a: 8
b: 555
()

>>> funkce(888,555,1,2,3)
a: 888
b: 555
(1, 2, 3)

>>> funkce(888,b=555,1,2,3)
  File "<ipython-input-46-edc32c0e4849>", line 1
    funkce(888,b=555,1,2,3)
SyntaxError: non-keyword arg after keyword arg
