code: @Nonnull
    public static <DATATYPE, ITEMTYPE extends ITreeItemWithID <String, DATATYPE, ITEMTYPE>> IMicroElement getTreeWithStringIDAsXML (@Nonnull final IBasicTree <DATATYPE, ITEMTYPE> aTree,
                                                                                                                                    @Nonnull final IConverterTreeItemToMicroNode <? super DATATYPE> aConverter)
    {
      return getTreeWithIDAsXML (aTree, IHasID.getComparatorID (), x -> x, aConverter);
    }
docs: Specialized conversion method for converting a tree with ID to a
  standardized XML tree.
  
  @param <DATATYPE>
  tree item value type
  @param <ITEMTYPE>
  tree item type
  @param aTree
  The tree to be converted
  @param aConverter
  The main data converter that converts the tree item values into XML
  @return The created document.