docs: def p_action_list(p):
      """
      action_list : action action_list
                  | action
      """
      if len(p) == 3:
          p[0] = p[1] + p[2]
      elif len(p) == 2:
          p[0] = p[1]
      else:
          raise RuntimeError("Invalid production rules 'p_action_list'")