python 统计文件top IP

lines = '''
1.2.2.3
1.21.29.19
....
'''

cnt = {}
for line in lines.split():
  if line not in cnt:
    cnt[line] = 0
  cnt[line] += 1

print cnt
out = cnt.items()
out.sort(lambda a,b:-cmp(a[1],b[1]))
print out