public class AddFromBranch : Sitecore.Pipelines.ItemProvider.AddFromTemplate.AddFromTemplateProcessor
    {
        public override void Process(AddFromTemplateArgs args)
        {
            Assert.ArgumentNotNull(args, nameof(args));

            if (args.Destination.Database.Name != "master") return;

            var templateItem = args.Destination.Database.GetItem(args.TemplateId);

            Assert.IsNotNull(templateItem, "Template did not exist!");

            // if this isn't a branch template, we can use the stock behavior
            if (templateItem.TemplateID != TemplateIDs.BranchTemplate) return;

            Assert.HasAccess((args.Destination.Access.CanCreate() ? 1 : 0) != 0, "AddFromTemplate - Add access required (destination: {0}, template: {1})", args.Destination.ID, args.TemplateId);

            // Create the branch template instance
            Item newItem = args.Destination.Database.Engines.DataEngine.AddFromTemplate(args.ItemName, args.TemplateId, args.Destination, args.NewId);

            // find all rendering data sources on the branch root item that point to an item under the branch template,
            // and repoint them to the equivalent subitem under the branch instance
            RewriteBranchRenderingDataSources(newItem, templateItem);

            // now go through all descendants to translate their data sources
            var newItemDescendants = newItem.Axes.GetDescendants();
            for (int i = 0; i < newItemDescendants.Length; i++)
            {
                RewriteBranchRenderingDataSources(newItemDescendants[i], templateItem);
            }

            args.Result = newItem;
        }

        protected virtual void RewriteBranchRenderingDataSources(Item item, BranchItem branchTemplateItem)
        {
            string branchBasePath = branchTemplateItem.InnerItem.Paths.FullPath;

            LayoutHelper.ApplyActionToAllRenderings(item, rendering =>
            {
                if (string.IsNullOrWhiteSpace(rendering.Datasource))
                    return RenderingActionResult.None;

                    // note: queries and multiple item datasources are not supported
                    var renderingTargetItem = item.Database.GetItem(rendering.Datasource);

                if (renderingTargetItem == null)
                    Log.Warn("Error while expanding branch template rendering datasources: data source {0} was not resolvable.".FormatWith(rendering.Datasource), this);

                    // if there was no valid target item OR the target item is not a child of the branch template we skip out
                    if (renderingTargetItem == null || !renderingTargetItem.Paths.FullPath.StartsWith(branchBasePath, StringComparison.OrdinalIgnoreCase))
                    return RenderingActionResult.None;

                var relativeRenderingPath = renderingTargetItem.Paths.FullPath.Substring(branchBasePath.Length).TrimStart('/');
                relativeRenderingPath = relativeRenderingPath.Substring(relativeRenderingPath.IndexOf('/')); // we need to skip the "/$name" at the root of the branch children

                    var newTargetPath = item.Paths.FullPath.Replace("Home", "").Replace("Global", "").TrimEnd('/') + relativeRenderingPath;

                var newTargetItem = item.Database.GetItem(newTargetPath);

                    // if the target item was a valid under branch item, but the same relative path does not exist under the branch instance
                    // we set the datasource to something invalid to avoid any potential unintentional edits of a shared data source item
                    if (newTargetItem == null)
                {
                    rendering.Datasource = "INVALID_BRANCH_SUBITEM_ID";
                    return RenderingActionResult.None;
                }

                rendering.Datasource = newTargetItem.ID.ToString();
                return RenderingActionResult.None;
            });
        }