code: def move_parent_up(self):
          
          cursor = self.nav.absolute_index
          if cursor > 0:
              level = max(self.content.get(cursor)['level'], 1)
              while self.content.get(cursor - 1)['level'] >= level:
                  self._move_cursor(-1)
                  cursor -= 1
              self._move_cursor(-1)
          else:
              self.term.flash()
  
          self.clear_input_queue()
docs: Move the cursor up to the comment's parent. If the comment is
          top-level, jump to the previous top-level comment.