python datetime 擷取n天後的時間日期

import datetime

now = datetime.datetime.now()
date_str = now.strftime("%Y-%m-%d")

date_after = ((now+datetime.timedelta(days=17)).strftime("%Y-%m-%d"))
print(date_str)
print(date_after)
           

# date_str: 2021-08-18
# date_after: 2021-09-04