如何用方形而不是圆形FSCalendar Swift 3选择日期单元格

import FSCalendar

class ViewController: UIViewController, FSCalendarDelegate, FSCalendarDataSource {
    var calendar: FSCalendar!
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        calendar = FSCalendar(frame: CGRect(x: 0, y: 0, width: 300, height: 300))
        calendar.delegate = self
        calendar.dataSource = self
        view.addSubview(calendar)
    }
}

func calendar(_ calendar: FSCalendar, appearance: FSCalendarAppearance, borderRadiusFor date: Date) -> CGFloat {
    return 0 // 设置日期单元格的边框半径为0，使其呈现方形
}

func calendar(_ calendar: FSCalendar, appearance: FSCalendarAppearance, fillDefaultColorFor date: Date) -> UIColor? {
    return UIColor.blue // 设置日期单元格的背景颜色为蓝色
}

func calendar(_ calendar: FSCalendar, appearance: FSCalendarAppearance, titleDefaultColorFor date: Date) -> UIColor? {
    return UIColor.white // 设置日期单元格的文字颜色为白色
}