code: def unindex_item(self, item):
          
          name_property = getattr(self.__class__, "name_property", None)
          if name_property is None:
              return
          name = getattr(item, name_property, None)
          if name is None:
              return
          self.name_to_item.pop(name, None)
docs: Un-index an item from our name_to_item dict.
          :param item: the item to un-index
          :type item: alignak.objects.item.Item
          :return: None