How to set accessibility-label to NSTextAttachment ?

I have the following method to insert @mentions to a text field:

    func insertMention(user: Token, at range: NSRange) -> Void {
        let tokenImage: UIImage = renderMentionToken(text: "@\(user.username)")
        
        let attachment: NSTextAttachment = NSTextAttachment()
        attachment.image = tokenImage
        attachment.bounds = CGRect(x: 0, y: -3, width: tokenImage.size.width, height: tokenImage.size.height)
        attachment.accessibilityLabel = user.username
        attachment.accessibilityHint = "Mention of \(user.username)"
        
        let attachmentString: NSMutableAttributedString = NSMutableAttributedString(attributedString: NSAttributedString(attachment: attachment))
        attachmentString.addAttribute(.TokenID, value: user.id, range: NSRange(location: 0, length: 1))
        attachmentString.addAttribute(.Tokenname, value: user.username, range: NSRange(location: 0, length: 1))
        
        let mutableText: NSMutableAttributedString = NSMutableAttributedString(attributedString: textView.attributedText)
        mutableText.replaceCharacters(in: range, with: attachmentString)
        mutableText.append(NSAttributedString(string: " "))

        textView.attributedText = mutableText
        textView.selectedRange = NSRange(location: range.location + 2, length: 0)

        mentionRange = nil
        tableView.isHidden = true
    }

When I use XCode's accessibility inspector to inspect the text input, the inserted token is not read by the inspector - instead a whitespace is shown for the token. I want to set the accessibility-label to the string content of the NSTextAttachment. How?

func insertMention(user: Token, at range: NSRange) -> Void {
    let tokenImage: UIImage = renderMentionToken(text: "@\(user.username)")
    
    let attachment: NSTextAttachment = NSTextAttachment()
    attachment.image = tokenImage
    attachment.bounds = CGRect(x: 0, y: -3, width: tokenImage.size.width, height: tokenImage.size.height)
    attachment.accessibilityLabel = user.username
    attachment.accessibilityHint = "Mention of \(user.username)"
    
    let attachmentString: NSMutableAttributedString = NSMutableAttributedString(attributedString: NSAttributedString(attachment: attachment))
    attachmentString.addAttribute(.TokenID, value: user.id, range: NSRange(location: 0, length: 1))
    attachmentString.addAttribute(.Tokenname, value: user.username, range: NSRange(location: 0, length: 1))
    
    let mutableText: NSMutableAttributedString = NSMutableAttributedString(attributedString: textView.attributedText)
    mutableText.replaceCharacters(in: range, with: attachmentString)
    mutableText.append(NSAttributedString(string: " "))

    textView.attributedText = mutableText
    textView.selectedRange = NSRange(location: range.location + 2, length: 0)

    mentionRange = nil
    tableView.isHidden = true
}#RUN
How to set accessibility-label to NSTextAttachment ?
 
 
Q