python两个日期相减

python两个日期相差多少天：

import datetime
d1 = datetime.datetime.strptime('2021-01-01 00:00:00', '%Y-%m-%d %H:%M:%S')
d2 = datetime.datetime.strptime('2020-01-01 00:00:00', '%Y-%m-%d %H:%M:%S')
delta = d1 - d2
print(delta.days)
# 366