code: def move_up(self):
          
          if self.current_item.parent is not None:
              self.current_item = self.current_item.parent
  
          for f in self._hooks["up"]:
              f(self)
          if self.current_item is self.root:
              for f in self._hooks["top"]:
                  f(self)
          return self
docs: Move up one level in the hierarchy, unless already on top.