docs: def _handle_sighup(myrpcserver, signum, unused):
      """Closes (terminates) all of its clients. Though keeps server running."""
      print("SIGHUP: stopping all clients",sys.stderr)
      if myrpcserver._closed:
          return
      for c in set(myrpcserver.clients):
          try:
              c.shutdown(socket.SHUT_RDWR)
          except Exception:
              pass
          c.close()
      myrpcserver.clients.clear()