generator functions: why won't this work?

[zillow20 at googlemail.com]

Hi all,

I'm trying to understand generator functions and the yield keyword.
I'd like to understand why the following code isn't supposed to work.
(What I would have expected it to do is, for a variable number of
arguments composed of numbers, tuples of numbers, tuples of tuples,
etc., the function would give me the next number "in sequence")
####################################
def getNextScalar(*args):
   for arg in args:
      if ( isinstance(arg, tuple)):
         getNextScalar(arg)
      else:
         yield arg
####################################

# here's an example that uses this function:
# creating a generator object:
g = getNextScalar(1, 2, (3,4))
g.next() # OK: returns 1
g.next() # OK: returns 2
g.next() # not OK: throws StopIteration error

####################################

I'm sure I'm making some unwarranted assumption somewhere, but I
haven't been able to figure it out yet (just started learning Python a
couple of days ago).

Any help will be appreciated :)

Akiel