知识付费使用PHP7.2以上版本时退款不成功；找到图中方法位置，按下面代码修改图中方法
public function AliPayRefund($out_trade_no, $trade_no, $refund_amount, $refund_reason, $passback_params)
{
$request = new \AlipayTradeRefundRequest();
$request->setBizContent(self::setBizContent(compact('out_trade_no', 'trade_no', 'refund_amount', 'refund_reason', 'passback_params')));
$result=self::AopclientRequestExecute($request);
$responseNode = str_replace(".", "_", $request->getApiMethodName()) . "_response";
$resultCode = $result->$responseNode->code;
return $resultCode;
}
