code: def _calculate_values_to_forecast(self, timeSeries):
          if self._forecastUntil is None:
              return
          if not timeSeries.is_sorted():
              raise ValueError("timeSeries has to be sorted.")
          if not timeSeries.is_normalized():
              raise ValueError("timeSeries has to be normalized.")
          timediff = timeSeries[-1][0] - timeSeries[-2][0]
          forecastSpan = self._forecastUntil - timeSeries[-1][0]
          self.set_parameter("valuesToForecast", int(forecastSpan / timediff) + 1)