Quick sort within 5 lines in python

def qs(ar):
    if len(ar) <= 1:
        return ar
    pvt = ar[len(ar) / 2]
    lft = [x1 for x1 in ar if x1 < pvt]
    md = [x1 for x1 in ar if x1 == pvt]
    right1 = [x1 for x1 in ar if x1 > pvt]
    return qs(lft) + md + qs(right1)

print qs([31,62,84,10,1,2,1])