Getting memory leak when converting HTML string to AttributedString

Getting memory leak when converting HTML string to AttributedString using below String extension

Usage:

self.lblHeader.attributedText = "<H1>Hello world</H1><h2><b>, abc</b><h2>".html2AttributedString

String extension for converting HTML to attributed string

extension String {
    var html2AttributedString: NSMutableAttributedString? {
    autoreleasepool {
        let htmlData = self.data(using: String.Encoding(rawValue: String.Encoding.utf16.rawValue))
        let options = [
            NSAttributedString.DocumentReadingOptionKey.documentType:
            NSAttributedString.DocumentType.html
        ] as [NSAttributedString.DocumentReadingOptionKey : Any]
        let attributedString = try? NSMutableAttributedString(
            data: htmlData ?? Data(),
            options: options,
            documentAttributes: nil)
    
       return attributedString
   }
  }
}

As I found a memory leak due to below the line:

let options = [
        NSAttributedString.DocumentReadingOptionKey.documentType:
        NSAttributedString.DocumentType.html
    ] as [NSAttributedString.DocumentReadingOptionKey : Any]

is there any alternative solution? let me know.