code: def _get_next_positional(self):
          
          active_parser = self.active_parsers[-1]
          last_positional = self.visited_positionals[-1]
  
          all_positionals = active_parser._get_positional_actions()
          if not all_positionals:
              return None
  
          if active_parser == last_positional:
              return all_positionals[0]
  
          i = 0
          for i in range(len(all_positionals)):
              if all_positionals[i] == last_positional:
                  break
  
          if i + 1 < len(all_positionals):
              return all_positionals[i + 1]
  
          return None
docs: Get the next positional action if it exists.