如何仅针对mailchimp列表显示字段值

Question

我正在尝试针对mailchimp列表获取字段值，并且我正在使用laravel 5.5创建API调用。当我在postman中点击获取url时它什么也没显示，并显示状态200OK。

这是我的控制器：

    let storyboard = UIStoryboard(name: "Main", bundle: Bundle.main)
    let firstViewController = storyboard.instantiateViewController(withIdentifier: "FirstViewController") as? FirstViewController
    let secondViewController = storyboard.instantiateViewController(withIdentifier: "SecondViewController") as? SecondViewController
    let thirdViewController = storyboard.instantiateViewController(withIdentifier: "ThirdViewController") as? ThirdViewController

    self.navigationController?.setViewControllers([firstViewController,secondViewController,thirdViewController], animated: false)

我做错了什么？非常感谢您的帮助！ 提前致谢