Embed Barcode in Pdf Page

I’m trying to add a barcode to an existing PDF page. I was following along with the tutorial Add charts, barcodes, and slides to PDF (gemboxsoftware.com) and at the document.AppendPage line I am getting a “PdfDocument does not contain a definition for AppendPage” error. Has this method changed in recent versions?

Do you have sample code for available for adding a GemBox.Document.TextBox to a GemBox.Pdf.PdfPage?

Thanks,
Jamey

It turns out that example had an extension class at the bottom of the file with the method I needed. This one was attributed to user error and can be closed. Thanks!