code: def last(self, count=1):
          
          if self._order_with:
              order = self._order_with.values()[0]
              order = "desc" if order == "asc" else "asc"
              order_with = self._order_with
              self._order_with = {}
              result = self.order_by(**{order_with.keys()[0]: order}).first(count)
              self._order_with = order_with
              return result
          else:
              return self.order_by(id="desc").first(count)
docs: Returns the last record in the query (sorting by id unless modified by
          `order_by`, whereupon it reverses the order passed in `order_by`).
          Returns None if the query has no records.