>>> def list_test1(w):
...    w = [1,1,1,1]
...    w[1] = 5
 
>>> def list_test2(w):
...    w[1] = 5
...    w = [1,1,1,1]

>>> k1 = [0, 0, 0]
>>> list_test1(k1)
>>> k1
[0, 0, 0]
>>> k2 = [0, 0, 0]
>>> list_test2(k2)
>>> k2
[0, 5, 0]