code: def find_unallocated_holdings(self):
          
          # Get linked securities
          session = self.open_session()
          linked_entities = session.query(AssetClassStock).all()
          linked = []
          # linked = map(lambda x: f"{x.symbol}", linked_entities)
          for item in linked_entities:
              linked.append(item.symbol)
  
          # Get all securities with balance > 0.
          from .stocks import StocksInfo
  
          stocks = StocksInfo()
          stocks.logger = self.logger
          holdings = stocks.get_symbols_with_positive_balances()
  
          # Find those which are not included in the stock links.
          non_alloc = []
          index = -1
          for item in holdings:
              try:
                  index = linked.index(item)
                  self.logger.debug(index)
              except ValueError:
                  non_alloc.append(item)
  
          return non_alloc
docs: Identifies any holdings that are not included in asset allocation