Help! Where's the error?

gistfile1.txt

def quickSortMath(values):
    if len(values)<=1:
        return values
    if len(values)==2:
        if values[1]<values[0]:
            values[0],values[1]=values[1],values[0]
        return values
    pivot=min(values)+(sum(values)/len(values))
    print pivot
    less=[]
    greater=[]
    for x in values:
        if x<=pivot:
            less.append(x)
        else:
            greater.append(x)
##    less=quickSortMath(less)
##    greater=quickSortMath(greater)

    return less+greater