docs: def list_load_areas(self, session, mv_districts):
          """list load_areas (load areas) peak load from database for a single MV grid_district
  
          Parameters
          ----------
          session : sqlalchemy.orm.session.Session
              Database session
          mv_districts: 
              List of MV districts
          """
  
          # threshold: load area peak load, if peak load < threshold => disregard
          # load area
          lv_loads_threshold = cfg_ding0.get('mv_routing', 'load_area_threshold')
          #lv_loads_threshold = 0
  
          gw2kw = 10 ** 6  # load in database is in GW -> scale to kW
  
          #filter list for only desired MV districts
          stations_list = [d.mv_grid._station.id_db for d in mv_districts]
  
          # build SQL query
          lv_load_areas_sqla = session.query(
              self.orm['orm_lv_load_areas'].id.label('id_db'),
              (self.orm['orm_lv_load_areas'].sector_peakload_residential * gw2kw).\
                  label('peak_load_residential'),
              (self.orm['orm_lv_load_areas'].sector_peakload_retail * gw2kw).\
                  label('peak_load_retail'),
              (self.orm['orm_lv_load_areas'].sector_peakload_industrial * gw2kw).\
                  label('peak_load_industrial'),
              (self.orm['orm_lv_load_areas'].sector_peakload_agricultural * gw2kw).\
                  label('peak_load_agricultural'),
              #self.orm['orm_lv_load_areas'].subst_id
              ). \
              filter(self.orm['orm_lv_load_areas'].subst_id.in_(stations_list)).\
              filter(((self.orm['orm_lv_load_areas'].sector_peakload_residential  # only pick load areas with peak load > lv_loads_threshold
                       + self.orm['orm_lv_load_areas'].sector_peakload_retail
                       + self.orm['orm_lv_load_areas'].sector_peakload_industrial
                       + self.orm['orm_lv_load_areas'].sector_peakload_agricultural)
                         * gw2kw) > lv_loads_threshold). \
              filter(self.orm['version_condition_la'])
  
          # read data from db
          lv_load_areas = pd.read_sql_query(lv_load_areas_sqla.statement,
                                            session.bind,
                                            index_col='id_db')
  
          return lv_load_areas