def _check_timeindex(self):
        """
        Check function to check if all feed-in and load time series contain
        values for the specified time index.

        """
        try:
            self.timeseries.generation_fluctuating
            self.timeseries.generation_dispatchable
            self.timeseries.load
            self.timeseries.generation_reactive_power
            self.timeseries.load_reactive_power
        except:
            message = 'Time index of feed-in and load time series does ' \
                      'not match.'
            logging.error(message)
            raise KeyError(message)