How to change background color of page indicator in UIPageViewController

Question

I use a UIPageViewController in storyboard, and write a class inherit from UIPageViewController.

After I finished code, I found the background color of page indicator is black, which I don't know how to change.

I search the internet, and found many people will use UIViewController+UIPageControl to do custom page indicator.

Is it possible to change the background color in UIPageViewController?

Thanks!