Hack for mongoid version differences

npv_hack.rb

def self.npv_item_for_security_id sec_id, swap_prices

      npv_items = swap_prices.npv_items.select do |item| 
         item['symbol'].eql?(sec_id)
      end

      return nil if npv_items.empty?

      npv_item = npv_items.last
      npv_item = npv_item.as_document unless npv_item.is_a?(Hash) 

      Java::Eris::NpvItem.from_h(npv_item)
end