public static ModelNode AddMasterPagePreview(this ModelNode model, MasterPagePreviewDefinition definition, Action<ModelNode> action)
 {
     return model.AddDefinitionNode(definition, action);
 }
 public static ModelNode AddMasterPagePreview(this ModelNode model, MasterPagePreviewDefinition definition)
 {
     return AddMasterPagePreview(model, definition, null);
 }