python的input函数设置timeout超时退出

import sys, select
def timeoutable_input(clue="",timeout=None):
    print(clue,end="")
    i, o, e = select.select([sys.stdin], [], [], timeout)
    return sys.stdin.readline() if len(i)>0 else None

#不设置timeout
timeoutable_input(clue="",timeout=None)
#设置timeout为5
timeoutable_input(clue="",timeout=5)