*args and Tuples

[millpond]

def func(*items):
     print(type(items)) 
     a=list(items)
     print(type(a))
     a[3]= 1026
     for i in a:
         print i

items=[1,3,7,9,-99,555,88]
func(*items[:]) 

I am trying to pass a list into *args(*items) and it insists on unpacking it into a tuple, whose immutability makes manipulation of data nigh impossible without converting it into a list.

In all examples I see the default usage of *args is to print, or do some things fairly useless. Being new, I might have overlooked something blazingly obvious - which is why I put this question here:

Is conversion to tuple in *args functions default behaviour for list(array) arguments?
And is there a simple way to call variable arguments and have them default to mutable data types? A decorator?