CS101 Starred problem 3

def ordered_search(index, ranks, keyword):
    index2= lookup(index,keyword)
    listA, listB, listC, listD = [],[],[], []
    print index2
    if len(index2)>1:
        pivot= ranks[index2[0]]
        for item in index2:
            if ranks[item]< pivot:
                listA.append(item)
            if ranks[item]== pivot:
                listB.append(item)
            if ranks[item]> pivot:
                listC.append(item)

    else:
        return index
    return ordered_search(listA, ranks,keyword)