def <<(item)
      item = ensure_type(Item, item)

      original_item = find_item(item)

      if original_item
        original_item.quantity += (item.quantity || 1)
      else
        store << item
      end
    end
def <<(item)
      item = ensure_type(Item, item)

      original_item = find_item(item)

      if original_item
        original_item.quantity += (item.quantity || 1)
      else
        store << item
      end
    end
Overriding standard method to add new objects