def print_list(x):
    if len(x) == 0:
        return
    first = x[0]
    rest = x[1:]
    print(first)   #print first item
    print_list(rest) #print the rest of the list.
def foo(x):
    if len(x) == 0:
        return
    first = x[0]
    rest = x[1:]
    foo(rest) #print the rest of the list.
    print(first)   #print first item

foo(["a", "b", "c", "d"])
foo(list(range(20)))