code: def time_until_expiration(self):
          
          if self.password_expires_at is not None:
              expiration_date = datetime.datetime.strptime(
                  self.password_expires_at, "%Y-%m-%dT%H:%M:%S.%f")
              return expiration_date - datetime.datetime.now()
docs: Returns the number of remaining days until user's password expires.
  
          Calculates the number days until the user must change their password,
          once the password expires the user will not able to log in until an
          admin changes its password.