python問題請教各位大神：希望實現壹個大txt文件隨機讀取其中幾句話並合成壹篇新文章，謝謝

import?random

with?open('a.txt','r')?as?f:

with?open('b.txt','w')?as?f2:

lines=f.readlines()

flen=len(lines)-1

for?i?in?range(1,random.randint(0,flen)):

f2.write(lines[random.randint(0,flen)])