yyyy mm dd hh mm in datetime pyhton code example

Example 1: python date from yy/mm/dd to yy-mm-dd

lastconnection = datetime.strptime("21/12/2008", "%d/%m/%Y").strftime('%Y-%m-%d')

Example 2: python datetime format yyyy-mm-dd

from datetime import datetime
now = datetime.today().isoformat()
print(now) # '2018-12-05T11:15:55.126382'