code: def select_previous(self):
          
          self.footer.clear_message()
  
          if self.selected == 0:
              self.footer.draw_message("Cannot move beyond first toot.", Color.GREEN)
              return
  
          old_index = self.selected
          new_index = self.selected - 1
  
          self.selected = new_index
          self.redraw_after_selection_change(old_index, new_index)
docs: Move to the previous status in the timeline.