React Fetch Delete失败，并进行飞行前响应

Question

我正在从react应用程序中进行访存删除，删除操作由aws lambda（python flask）处理。

反应获取代码

fetch(url, {
        'method'  : 'DELETE',
        headers: {
            'Accept': '*',
            'Access-Control-Request-Method': 'DELETE',
            'Access-Control-Request-Headers': 'Content-Type',
            "Access-Control-Allow-Methods": "DELETE",
            "Content-Type": "application/json",
            "Access-Control-Allow-Headers": "Content-Type",
            "Access-Control-Max-Age": "86400"
        }
    }).then(response => Promise( response.json()))
        .then(( responseJson) => {
            console.log("response json is " + responseJson)
        })
        .catch(error => {
                console.log(error)

            }
        )

使用python来lambda

headers = {
        "Access-Control-Allow-Methods": "GET, POST, PATCH, PUT, DELETE, OPTIONS",
        "Content-Type": "application/json",
        "Access-Control-Allow-Origin": "*",
    }


return testjson, 200, headers

错误：

访问CORS策略已阻止从原点“ https://xxx.amazonaws.com/Prod/api/2516”获取“ http://localhost:3000”的访问权限：Access-Control-Allow-不允许请求标头字段access-control-allow-headers-飞行前响应中出现标题。