func applyShadow(shadowColor: UIColor, shadowWidth: CGFloat,
                     shadowHeigt: CGFloat, shadowRadius: CGFloat,
                     subString: String) {
        if let range = self.string.range(of: subString) {
            self.applyShadow(shadowColor: shadowColor, shadowWidth: shadowWidth,
                             shadowHeigt: shadowHeigt, shadowRadius: shadowRadius,
                             onRange: NSRange(range, in: self.string))
        }
    }
    func applyShadow(shadowColor: UIColor, shadowWidth: CGFloat,
                     shadowHeigt: CGFloat, shadowRadius: CGFloat,
                     onRange: NSRange) {
        let shadow = NSShadow()
        shadow.shadowOffset = CGSize(width: shadowWidth, height: shadowHeigt)
        shadow.shadowColor = shadowColor
        shadow.shadowBlurRadius = shadowRadius
        self.addAttributes([NSAttributedString.Key.shadow : shadow], range: onRange)
    }