Set UIView hidden with fade animated

UIView+Animation.swift

extension UIView {
    func setHidden(_ isHidden: Bool, animated: Bool, completion: (() -> Void)? = nil) {
        if animated {
            let startAlpha: CGFloat
            let animatingAlpha: CGFloat
            if isHidden {
                startAlpha = 1
                animatingAlpha = 0
            } else {
                startAlpha = 0
                animatingAlpha = 1
            }
            alpha = startAlpha
            UIView.animate(withDuration: 0.25, delay: 0.1,
                           options: .curveEaseOut, animations: { [weak self] in
                            self?.alpha = animatingAlpha
                }, completion: { [weak self] _ in
                    self?.isHidden = isHidden
                    self?.alpha = 1.0
                    completion?()
            })
        } else {
            self.isHidden = isHidden
            completion?()
        }
    }
}