我试图更新价格和数量的我的产品变体在Shopify使用cURL和PHP下面我的代码：

$url=$api_url.'/admin/api/2020-01/变体/31941936382042.json'；

    $data_json = json_encode(
        array(
            'variants' => array(
                'id' => 4574444978266,
                'sku' => 'TEST-SKU-111',
                'price' => 20,
                'compare_at_price' => 20,
                'cost' => 20, // This price will be coming form database
                'inventory_quantity' => 10))
    );

    var_dump($data_json);


    $ch = curl_init();

    curl_setopt($ch, CURLOPT_URL, $url);
    curl_setopt($ch, CURLOPT_HTTPHEADER, array('Content-Type: application/json; charset=utf-8', 'Content-Length: ' . strlen($data_json)));
    curl_setopt($ch, CURLOPT_CUSTOMREQUEST, 'PUT');
    curl_setopt($ch, CURLOPT_POSTFIELDS, $data_json);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
    $response = curl_exec($ch);
    var_dump($response);
    curl_close($ch);

当我每次测试它时，它都会说：

{“errors”：{“variant”：“必需参数丢失或无效”}

我检查了官方文件https://shopify.dev/docs/admin-api/rest/reference/products/product-variant#update-2020-01，但仍然没有运气。有人能纠正我的错误吗？

提前感谢