Adding a moder news page from CSOM

AddModernNewsPage

AuthenticationManager authManager = new AuthenticationManager();
            ClientContext context =
                authManager.GetSharePointOnlineAuthenticatedContextTenant(url, user, password);

            var pageName = string.Format("ModernNewsPage_{0}.aspx", DateTime.Now.ToString("yyyyMMdd_HHmmss"));
            
            List pagesLibrary = context.Web.GetListByTitle("Site Pages");
            var pagesLibraryUrl = pagesLibrary.RootFolder.ServerRelativeUrl;
            var newPageUrl = pagesLibraryUrl + "/" + pageName;

            ListItem item = 
                pagesLibrary.RootFolder.Files.AddTemplateFile(newPageUrl, TemplateFileType.ClientSidePage).ListItemAllFields;
            // Make this page a "modern news article page"
            item["ContentTypeId"] = "0x0101009D1CB255DA76424F860D91F20E6C4118";
            item["Title"] = System.IO.Path.GetFileNameWithoutExtension(pageName);
            item["ClientSideApplicationId"] = "b6917cb1-93a0-4b97-a84d-7cf49975d4ec";
            item["PageLayoutType"] = "Article";
            item["PromotedState"] = "2";
            item["CanvasContent1"] = "<div></div>";
            item["FirstPublishedDate"] = DateTime.Now;
            item["BannerImageUrl"] = "/_layouts/15/images/sitepagethumbnail.png";
            item.Update();
            context.Load(item);
            context.ExecuteQuery();