Is there a better algorithm?

[Kottiyath]

I have the following list of tuples:
L = [(1, 2), (3, 4, 5), (6, 7)]

I want to loop through the list and extract the values.
The only algorithm I could think of is:
>>> for i in l:
...  u = None
...  try:
...   (k, v) = i
...  except ValueError:
...   (k, u, v) = i
...  print k, u, v
---------
1 None 2
3 4 5
6 None 7
-------------
But, this algorithm doesnt look very beautiful - like say -> for k, u,
v in L:
Can anyone suggest a better algorithm to get the values?