python 判断某时间是否在七天内

import dateutil

import datetime

def isSevenTime(test_time):
    cc = str(dateutil.parser.parse(test_time))
    obj_time = datetime.datetime.strptime(cc[:18], "%Y-%m-%d %H:%M:%S")
    now = str(datetime.datetime.now())
    qitian = datetime.datetime.strptime(now[:18], "%Y-%m-%d %H:%M:%S")
    days = (qitian - obj_time).days
    if days < 7:
        return True
    return False