Local variables and while loops (1)
Note that in a while loop,
      variables are local
def aFunction():
  n = 0
  while n < 10:
    n = n+1
aFunction()
print nprints:
Traceback (most recent call last):
  File "local2.py", line 7, in ?
    print n
NameError: name 'n' is not defined