code: def timeseries(self):
          
          if self._timeseries is None:
  
              if isinstance(self.grid, MVGrid):
                  voltage_level = 'mv'
              elif isinstance(self.grid, LVGrid):
                  voltage_level = 'lv'
  
              ts_total = None
              for sector in self.consumption.keys():
                  consumption = self.consumption[sector]
  
                  # check if load time series for MV and LV are differentiated
                  try:
                      ts = self.grid.network.timeseries.load[
                          sector, voltage_level].to_frame('p')
                  except KeyError:
                      try:
                          ts = self.grid.network.timeseries.load[
                              sector].to_frame('p')
                      except KeyError:
                          logger.exception(
                              "No timeseries for load of type {} "
                              "given.".format(sector))
                          raise
                  ts = ts * consumption
                  ts_q = self.timeseries_reactive
                  if ts_q is not None:
                      ts['q'] = ts_q.q
                  else:
                      ts['q'] = ts['p'] * self.q_sign * tan(
                          acos(self.power_factor))
  
                  if ts_total is None:
                      ts_total = ts
                  else:
                      ts_total.p += ts.p
                      ts_total.q += ts.q
  
              return ts_total
          else:
              return self._timeseries
docs: Load time series
  
          It returns the actual time series used in power flow analysis. If
          :attr:`_timeseries` is not :obj:`None`, it is returned. Otherwise,
          :meth:`timeseries()` looks for time series of the according sector in
          :class:`~.grid.network.TimeSeries` object.
  
          Returns
          -------
          :pandas:`pandas.DataFrame<dataframe>`
              DataFrame containing active power in kW in column 'p' and
              reactive power in kVA in column 'q'.