code: def set(self, k, v, obj='override'):
          'obj is a Sheet instance, or a Sheet [sub]class.  obj="override" means override all; obj="default" means last resort.'
          if k not in self:
              self[k] = dict()
          self[k][self.objname(obj)] = v
          return f set(self, k, v, obj='override'):
          'obj is a Sheet instance, or a Sheet [sub]class.  obj="override" means override all; obj="default" means last resort.'
          if k not in self:
              self[k] = dict()
          self[k][self.objname(obj)] = v
          return v
docs: obj is a Sheet instance, or a Sheet [sub]class.  obj="override" means override all; obj="default" means last resort.