code: def next_theme(self):
          
          theme = self.term.theme_list.next(self.term.theme)
          while not self.term.check_theme(theme):
              theme = self.term.theme_list.next(theme)
  
          self.term.set_theme(theme)
          self.draw()
          message = self.term.theme.display_string
          self.term.show_notification(message, timeout=1)
docs: Cycle to preview the next theme from the internal list of themes.