Braintree\Configuration::gateway PHP Method

    public static function gateway()
    {
        return new Gateway(self::$global);
    }

 /**
  * settlement pending a transaction by id in sandbox
  *
  * @param string $id transaction id
  * @param Configuration $config gateway config
  * @return Transaction
  */
 public static function settlementPending($transactionId)
 {
     return Configuration::gateway()->testing()->settlementPending($transactionId);
 }