UIPageControl 通过KVC改变圆点

想要改变UIPageControl原来的样式  简单有效

[_pageControl setValue:[UIImage imageWithColor:ColorFrom16(0xE6E6E6) size:CGSizeMake(25, 2)] forKeyPath:@"_pageImage"];

[_pageControl setValue:[UIImage imageWithColor:ColorFrom16(0xFFC778) size:CGSizeMake(25, 2)] forKeyPath:@"_currentPageImage"];