if let presentationMapVersionString = element["Presentation"]["PresentationMap"].attributes["Version"],
            let presentationMapVersion = Int(presentationMapVersionString),
            let presentationMapUriString = element["Presentation"]["PresentationMap"].attributes["Uri"],
            let presentationMapUri = URL(string: presentationMapUriString) {
            presentationMap = Presentation(uri: presentationMapUri, version: presentationMapVersion)