code: def box_it_up(self):
          
          for k in self:
              _conversion_checks(k, self.keys(), self._box_config,
                                 check_only=True)
              if self[k] is not self and hasattr(self[k], 'box_it_up'):
                  self[k].box_it_up()
docs: Perform value lookup for all items in current dictionary,
          generating all sub Box objects, while also running `box_it_up` on
          any of those sub box objects.