二分法10个硬币找一个假币

import random
def FindMoney(aList):
    if len(aList) == 2:
        if aList[0] > aList[1]:
            print aList[1]
        else:
            print aList[0]
    else:
        if sum(aList[len(aList)/2:]) > sum(aList[:len(aList)/2]):
            FindMoney(aList[:len(aList)/2])
        else:
            FindMoney(aList[len(aList)/2:])
            
a = [10] *9 + [9]
a.sort(lambda a,b: random.randint(-1, 1))
print a
FindMoney(a)
怎么修改