docs: def p_setting_list(p):
      """
      setting_list : setting setting_list
                   | setting
      """
      if len(p) == 3:
          p[0] = merge_map(p[1], p[2])
      elif len(p) == 2:
          p[0] = p[1]
      else:
          raise RuntimeError("Invalid production rules 'p_setting_list'")