Email Composer with Attributed String

Updated to swift 5 Xcode 12.1

var cookedString : String!
let attributeString = myTextView.attributedText

    let documentAttributes = [NSAttributedString.DocumentAttributeKey.documentType: NSAttributedString.DocumentType.html]
        do
        {
            let htmlData = try attributeString!.data(from: NSMakeRange(0, attributeStrung!.length), documentAttributes: documentAttributes)
            if let htmlString = String(data: htmlData, encoding: String.Encoding.utf8)
            {
                cookedString = htmlString
            }
        }
        catch
        {
            print("error creating HTML from Attributed String")
        } let mailComposerVC = MFMailComposeViewController()
mailComposerVC.mailComposeDelegate = self
mailComposerVC.setMessageBody(cookedString, isHTML: true)