获取python的版本&获取两个日期的天数差值

import sys

from datetime import datetime

# Syntax sugar.
_ver = sys.version_info  # 获取python版本

#: Python 2.x?
is_py2 = (_ver[0] == 2)     # is_py2 类型为布尔型，返回 False 或 True

#: Python 3.x?
is_py3 = (_ver[0] == 3)

retire_day = datetime(2020, 1, 1)
today = datetime.now()
left_days = (retire_day - today).days   # 获取两个日期的天数差值

if left_days > 0:
    retire_msg = "Python 2 will retire in {} days, why not move to Python 3?".format(left_days)
else:
    retire_msg = "Python 2 has been retired, you should move to Python 3."

print(_ver, "
", is_py2, is_py3)
print(retire_msg)