code: func handleNotifyNewTransactions(wsc *wsClient, icmd interface{}) (interface{}, error) {
  	cmd, ok := icmd.(*btcjson.NotifyNewTransactionsCmd)
  	if !ok {
  		return nil, btcjson.ErrRPCInternal
  	}
  
  	wsc.verboseTxUpdates = cmd.Verbose != nil && *cmd.Verbose
  	wsc.server.ntfnMgr.RegisterNewMempoolTxsUpdates(wsc)
  	return nil, nil
  }
docs: // handleNotifyNewTransations implements the notifynewtransactions command
  // extension for websocket connections.