如何在UITextView中为特定的单词设置样式？

let textView = UITextView()
let text = textView.text ?? ""
let attributedText = NSMutableAttributedString(string: text)

let attributes: [NSAttributedString.Key: Any] = [
    .font: UIFont.boldSystemFont(ofSize: 16),
    .foregroundColor: UIColor.red
]

text.enumerateSubstrings(in: text.startIndex..<text.endIndex, options: .byWords) { (substring, _, _, _) in
    if let word = substring, word == "特定单词" {
        attributedText.addAttributes(attributes, range: NSRange(text.range(of: word)!, in: text))
    }
}

textView.attributedText = attributedText