Description: ------------ Congratulations on this package! One annoyance I've run across is that I end up duplicating the callback function for _walk a lot. This is because, for example, I want to print the tree out with different indentation, or extra text strings by each item. The base code is the same for each function, therefore it would be cleaner if I could pass extra data to the callback function - by using call_user_func_array and having an extra parameter to pass to the method walk (and hence to _walk)