code: @SuppressWarnings("unchecked")
      public A addAll(Iterable<Property> toAdd) {
          Data data = getData();
          Data modified = data.addAll(toAdd);
          if (data == modified) {
              return (A)this;
          }
  
          return copy(delegate.put("data", Property.toArrayNode(data)));
      }
docs: Adds properties to the data.
  @param toAdd the properties to add
  @return a new copy of the template.