merge sort with python

merge_sort.py

#! usr/bin/env python
#-*- coding:utf-8 -*-
#merge_sort.py

import sys

def merge(l,r):
	result = []
	while l != [] and r != []:
		if l[0] < r[0]:
			result.append(l.pop(0))
		elif l[0] >= r[0]:
			result.append(r.pop(0))
	return result + l + r

def div(lst):
	if len(lst) == 1:
		return lst
	mid = len(lst)/2
	l = div(lst[0:mid])
	r = div(lst[mid:len(lst)])
	return merge(l,r)

if __name__ == "__main__":
	lst = [1,3,4,5,2,8,9,11]
	div(lst)