serverless response format

https://aws.amazon.com/premiumsupport/knowledge-center/malformed-502-api-gateway/

 var response = {
        "statusCode": 200,
        "headers": {
            "my_header": "my_value"
        },
        "body": JSON.stringify(responseBody),
        "isBase64Encoded": false
    };
    callback(null, response);