code: def compute(self, write_to_tar=True):
          
          data = self._get_all_data(self.start_date, self.end_date)
          logging.info('Computing timeseries for {0} -- '
                       '{1}.'.format(self.start_date, self.end_date))
          full, full_dt = self._compute_full_ts(data)
          full_out = self._full_to_yearly_ts(full, full_dt)
          reduced = self._apply_all_time_reductions(full_out)
          logging.info("Writing desired gridded outputs to disk.")
          for dtype_time, data in reduced.items():
              data = _add_metadata_as_attrs(data, self.var.units,
                                            self.var.description,
                                            self.dtype_out_vert)
              self.save(data, dtype_time, dtype_out_vert=self.dtype_out_vert,
                        save_files=True, write_to_tar=write_to_tar)
          return self
docs: Perform all desired calculations on the data and save externally.