docs: def _get_all_group_items(network_id):
      """
          Get all the resource group items in the network, across all scenarios
          returns a dictionary of dict objects, keyed on scenario_id
      """
      base_qry = db.DBSession.query(ResourceGroupItem)
  
      item_qry = base_qry.join(Scenario).filter(Scenario.network_id==network_id)
  
      x = time.time()
      logging.info("Getting all items")
      all_items = db.DBSession.execute(item_qry.statement).fetchall()
      log.info("%s groups jointly retrieved in %s", len(all_items), time.time()-x)
  
  
      logging.info("items retrieved. Processing results...")
      x = time.time()
      item_dict = dict()
      for item in all_items:
  
          items = item_dict.get(item.scenario_id, [])
          items.append(item)
          item_dict[item.scenario_id] = items
  
      logging.info("items processed in %s", time.time()-x)
  
      return item_dict