convert to swift NSMutableAttributedString

html.swift

var htmlString = NSMutableAttributedString()
do {
    if let data = self.data(using: String.Encoding.unicode, allowLossyConversion: true) {
        htmlString = try NSMutableAttributedString(data: data, options: [.documentType: NSAttributedString.DocumentType.html], documentAttributes: nil)
    }
} catch {
    print(error)
}