code: def get_trips(self, timestamp, start, via, destination, departure=True, prev_advices=1, next_advices=1):
          
          timezonestring = '+0100'
          if is_dst('Europe/Amsterdam'):
              timezonestring = '+0200'
          url = 'http://webservices.ns.nl/ns-api-treinplanner?'
          url = url + 'fromStation=' + start
          url = url + '&toStation=' + destination
          if via:
              url = url + '&via=' + via
          if len(timestamp) == 5:
              # Format of HH:MM - api needs yyyy-mm-ddThh:mm
              timestamp = time.strftime("%Y-%m-%d") + 'T' + timestamp
              #requested_time = datetime.strptime(timestamp, "%Y-%m-%dT%H:%M")
              # TODO: DST/normal time
              requested_time = load_datetime(timestamp + timezonestring, "%Y-%m-%dT%H:%M%z")
          else:
              #requested_time = datetime.strptime(timestamp, "%d-%m-%Y %H:%M")
              requested_time = load_datetime(timestamp + timezonestring, "%d-%m-%Y %H:%M%z")
              timestamp = datetime.strptime(timestamp, "%d-%m-%Y %H:%M").strftime("%Y-%m-%dT%H:%M")
          url = url + '&previousAdvices=' + str(prev_advices)
          url = url + '&nextAdvices=' + str(next_advices)
          url = url + '&dateTime=' + timestamp
          raw_trips = self._request('GET', url)
          return self.parse_trips(raw_trips, requested_time)
docs: Fetch trip possibilities for these parameters
          http://webservices.ns.nl/ns-api-treinplanner?<parameters>
          fromStation
          toStation
          dateTime: 2012-02-21T15:50
          departure: true for starting at timestamp, false for arriving at timestamp
          previousAdvices
          nextAdvices