forwarding *arg parameter

[Tuomas]

Steven D'Aprano wrote:
<snip>
> You could write something like this:
> 
> def g(*arg):
>     # Detect the special case of a single tuple argument
>     if len(arg) == 1 and type(arg[0]) == tuple:
>         return arg[0]
>     else:
>         return arg
> 
> but now tuple arguments are treated differently to all other data. Why do
> you think you need that?

I am looking a shorter way to do the above in the case:

def g(*arg):
     return arg

def f(*arg):
     return g(arg)

How can g know if it is called directly with (('foo', 'bar'),) or via f 
with ('foo', 'bar'). I coud write in f: return g(arg[0], arg[1]) if I 
know the number of arguments, but what if I don't know that in design time?

TV