scope of optional arguments

[cseja]

If I call

print walk([1,2,3], [])
print walk([5,6,7])

I get

[1, 2, 3]
[4, 5, 6]

but when I call

print walk([1,2,3])
print walk([5,6,7])

I get

[1, 2, 3]
[1, 2, 3, 4, 5, 6]

at stdout, where

def walk(seq, result = []):
  for item in seq:
    result.append(item)
  return result

Does that mean that the scope of optional arguments is global if they aren't 
used and local if they are (or am I missing something here)?

Regards,
CS