How much days left from today to given date

import datetime

today = datetime.date.today()
future = datetime.date(2019,9,20)
diff = future - today
print (diff.days)

diff is a timedelta object.

subtract them.

>>> from datetime import *
>>> today = date.today()
>>> future = date(2015,05,20)
>>> str(future - today)
'1326 days, 0:00:00'
>>> (future - today).days
1326