docs: def _next_radiotap_extpm(pkt, lst, cur, s):
      """Generates the next RadioTapExtendedPresenceMask"""
      if cur is None or (cur.present and cur.present.Ext):
          st = len(lst) + (cur is not None)
          return lambda *args: RadioTapExtendedPresenceMask(*args, index=st)
      return None