code: def parse_date(my_date):
          
          if isinstance(my_date, datetime.datetime):
              result = my_date
          elif isinstance(my_date, str):
              result = datetime.datetime.strptime(my_date, '%Y-%m-%dT%H:%M:%SZ')
          else:
              raise ValueError('Unexpected date format for "%s" of type "%s"' % (
                  str(my_date), type(my_date)))
          assert result.tzinfo is None, 'Unexpected tzinfo for date %s' % (
              result)
          return result
docs: Parse a date into canonical format of datetime.dateime.
  
          :param my_date:    Either datetime.datetime or string in 
                             '%Y-%m-%dT%H:%M:%SZ' format.
  
          ~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-
  
          :return:  A datetime.datetime.
  
          ~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-
  
          PURPOSE:  Parse a date and make sure it has no time zone.