1.  The following functions attempt to swap the contents of two lists.  For
each function state whether or not it works.  If it doesn't work, explain
why not.

a.
def list_swap1(a, b):
    temp = a
    a = b
    b = temp

b.
def list_swap2(a, b):
    temp = a[:]
    a = b[:]
    b = temp[:]

c.
def list_swap3(a, b):
    for i in range(len(a)):
        temp = a[i]
        a[i] = b[i]
        b[i] = temp