獲取python的版本&獲取兩個日期的天數差值

import sys

from datetime import datetime

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

#: Python 2.x?
is_py2 = (_ver[0] == 2)     # is_py2 類型為布爾型，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   # 獲取兩個日期的天數差值

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, "\n", is_py2, is_py3)
print(retire_msg)