quicksort in python

def quicksort(l):
	work = [(0,len(l)-1)]
	while work:
		(left,right) = work.pop()
		if right < left: 
			continue
		i_piv = left
		piv = l[i_piv]
		l0,r0 = left, right
		while left<right:
			while l[left] <= piv and left < right: left += 1
			while l[right] > piv: right -= 1
			if left < right: l[left], l[right] = l[right], l[left]
		l[i_piv], l[right] = l[right], piv
		work.append((l0,right-1))
		work.append((right+1,r0))